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Circulating tumour DNA (ctDNA) is defined as short DNA sequences shed by tumour cells into the systemic circulation. A promising use of ctDNA includes the detection of minimal residual disease (MRD) and is currently being studied in multiple types of solid tumours. Literature for the use of individualised ctDNA in nasopharyngeal carcinoma (NPC) is not available, although circulating Epstein-Barr virus DNA level is validated as a prognostic factor. We present a man in his 40s diagnosed with stage IV NPC who was started on chemotherapy with cis-platinum and gemcitabine. Serial monitoring of ctDNA completed to aid in detecting MRD after treatment demonstrated initial up-trending values correlating with subsequent imaging findings showing progression. Reinitiation of a different chemotherapy regimen significantly improved the ctDNA level, with corresponding imaging exhibiting a similar response. This case provides insight into the potential use of ctDNA in NPC and the benefit of serial ctDNA monitoring during treatment.

Thrombotic thrombocytopenic purpura (TTP) is a type of thrombotic microangiopathy that is characterized by microangiopathic haemolytic anaemia, consumption thrombocytopenia and organ injury. It is caused by a severe deficiency of ADAMTS13, which can be either congenital or acquired. There is a plethora of things that can cause the acquired form, including medications and infections. Vaccines have also been shown to cause TTP. In the midst of the COVID-19 pandemic, with multiple new vaccines being developed and distributed to the masses, the medical community needs to be aware of adverse events associated with these new vaccines. We present a case of TTP following administration of the Moderna booster vaccine.

Background: Circulating tumor DNA (ctDNA) are short DNA sequences shed by tumor cells into the systemic circulation. Studies have shown potential utility of the test to predict relapse or recurrence following treatment in solid tumors, but sensitivity and specificity have varied widely, ranging from 19-100% and 80-100% respectively, in breast cancer specifically. Moreover, literature describing the utility of monitoring dynamic changes in ctDNA trends is limited. We aim to evaluate the correlation between ctDNA test, both single test as well as dynamic trends in value over time, with imaging findings. Methods: We retrospectively analyzed the medical records of all adult patients diagnosed with breast cancer who underwent ctDNA testing at the hematology-oncology clinic at William Beaumont - Royal Oak and Troy Hospitals, Michigan, from August 2017 to June 2022. Patients who had ctDNA testing done but did not have imaging to correlate it with were excluded from the study. We calculated the sensitivity and specificity of a single positive ctDNA test to detect disease progression or residual disease on imaging. In patients with multiple ctDNA tests, we calculated the sensitivity and specificity of dynamic trends in ctDNA values to detect progression, regression, or absence of disease on imaging. Moreover, we calculated the lead time for positive ctDNA results to detect disease progression compared to imaging. Results: Nineteen patients were included in the study, with 34 total ctDNA test results, each utilized as a separate data point to compare with corresponding imaging findings (Table 1). Ten out of the 19 patients had multiple(>=2) ctDNA test results reported, with a total of 15 pairs of ctDNA values and each pair was analyzed separately as up trending (N=7), down trending (N=4), or persistent negative (N=4) to compare with a corresponding pair of imaging findings (Table 2). The median age at diagnosis was 55 years, and 94.7% were female. At diagnosis, majority of patients (68.4%) had either stage III or IV disease. Our primary endpoint, the correlation of single positive ctDNA result with imaging showing either progression or residual disease, showed a sensitivity and specificity of 100% and 93.3%, respectively. Secondarily, serial ctDNA trend analysis in ten patients revealed both sensitivity and specificity of 100% for up-trending ctDNA values to detect progression, down-trending to detect regression, and persistent negative results to detect absence of disease on imaging, respectively. The positive ctDNA results detected disease progression with a median lead time of 44.5 days compared to imaging. Conclusion: Given the high sensitivity and specificity to detect disease progression and regression in breast cancer patients by single ctDNA results and dynamic ctDNA trends in our study, we conclude that this may be a valid way to reliably monitor for changes in disease status before they become evident in imaging studies. Further clinical studies are required to prove the utility of ctDNA to detect changes in disease status and to guide therapeutic interventions in breast cancer. Table 1. Correlation of single ctDNA result with imaging findings. Table 2. Correlation of dynamic trends in ctDNA values with imaging findings. Citation Format: Ujjwal Karki, Bipin Ghimire, Emma Herrman, Siddhartha Yadav, Mohammad Muhsin Chisti. Detection of progression or regression of breast cancer by circulating tumor DNA (ctDNA) [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P1-05-07.

Merkel cell carcinoma (MCC) is a rare, rapidly growing, and aggressive dermatological neoplasm. It is commonly reported in Caucasian ethnicities, and almost 50% of the patients have a concomitant malignancy and are on immunosuppressive chemotherapy. Here, we present a 79-year-old woman with a history of relapsed Stage II, grade III follicular lymphoma, receiving maintenance rituximab infusions. She presented with a raised erythematous papule on her left cheek. An excisional biopsy of the lesion confirmed a diagnosis of Merkel cell carcinoma. After which, she underwent a wider excision with 1-2 cm margins. PET scan did not reveal any FDG-avid uptake lesions that would be concerning for metastatic disease. However, she underwent a sentinel lymph node biopsy which was also negative. Thus, the diagnosis was finalized as Stage I (T1 N0 M0) MCC. There are only two reported cases in literature about the significant progression of Merkel cell carcinoma in patients who coincidentally were receiving rituximab as a part of treatment for another disease. This raises questions for future investigation and research on whether there is a direct association between rituximab use specifically and the rapid growth of MCC.

Introduction Triple-negative breast cancer (TNBC) in men is very rare. The clinical characteristics, prognostic factors, and overall survival of men with TNBC have not been characterized. Methods The study population consisted of men and women with a diagnosis of stage I-III TNBC between 2010 and 2016 in the National Cancer Database. Baseline demographic and tumor characteristics between men and women were compared using Pearson's Chi-Square test for categorical variables and Mann-Whitney U test for continuous variables. Kaplan–Meier and multivariate Cox proportional hazards regression model was used to compare survival and identify prognostic factors. Results A total of 311 men and 95,406 women with TNBC were included in the final analysis. The 3-year and 5-year overall survival was 74.8% and 68.8% in men, while it was 83.2% and 74.8% in women, respectively. In multivariate analysis, men were found to have a significantly worse overall survival compared to women (HR, 1.49, 95% CI, 1.19-1.86, P= .01). Older age at diagnosis, higher TNM stage, undergoing mastectomy and not undergoing chemotherapy or radiation were identified as independent negative prognostic factors in men with TNBC. Conclusion In one of the largest studies of men with TNBC, men were noted to have a poorer overall survival compared to women, despite adjusting for usual prognostic factors. Further research into differences in tumor biology, treatment patterns and compliance with therapy between men and women are needed to understand the underlying etiologies for the survival difference in TNBC.

Fusion of b2a2 is the most common BCR/ABL rearrangement in CML; however, absent a2 exons are very rare. We describe a case with Philadelphia-positive chronic myeloid leukemia (CML) with a very rare b3a3 (e14a3) BCR/ABL junction. To our knowledge, only 15 such cases of CML have previously been reported. These uncommon transcripts may be under-reported, since RT-PCR-based assays may fail to detect these fusions due to the location of the primers and probes used. We are reporting this case for the first time which presented with MTHFR mutation and significant thrombocytosis. There is very limited information on how this genotype expresses and responds to treatment, especially to tyrosine kinase inhibitors, as compared to classic CML. Also, the relationship between MTHFR mutation and CML is not clear, although studies have been done.

We report a 74-year-old female who presented to the emergency department complaining of bruising and stroke-like symptoms. She underwent a negative stroke work-up but was found to have profoundly low platelets and splenomegaly on examination. An abdominal CT scan was ordered, showing pelvic lymphadenopathy. Lymphoma was suspected. However, subsequent bone marrow and lymph node biopsies showed no evidence of this. She was treated for immune thrombocytopenia purpura (ITP) to no avail while a lymphoma work-up continued. Months later, a third and final lymph node biopsy yielded evidence of Hodgkin disease (HD) and she began treatment shortly thereafter. She is currently undergoing standard treatment for this malignancy and her platelet counts have normalized. The case not only outlines the importance of the physician’s gestalt in arriving at the proper diagnosis, but it also posits the thought that perhaps ITP should be considered a paraneoplastic syndrome of HD.

Catastrophic antiphospholipid syndrome (CAPS) is a rare but severe form of antiphospholipid syndrome (APS). The syndrome manifests itself as a rapidly progressive multiorgan failure that is believed to be caused by widespread micro-thrombosis. Seldom does bleeding comanifest with thrombosis. We present a patient with APS who presented with nausea, vomiting and fatigue, and rapidly progressed into multiorgan failure before being diagnosed with CAPS. The clinical course was complicated by an atraumatic intracranial haemorrhage which demanded discontinuation of anticoagulation. The patient was treated with high dose steroid, intravenous immunoglobulin, followed by weekly rituximab infusion. Although the trigger for CAPS was not obvious during her hospital stay, she was diagnosed with acute cytomegalovirus (CMV) infection soon after discharge. In this case report, we explore the differential diagnoses of CAPS, investigate the possibility of CMV infection as a potential trigger, present the therapeutic challenges of anticoagulation and discuss the emerging use of rituximab.

Poster: "RANZCR-AOCR 2012 / R-0001 / The Correlation between Lymphoma Cell Size and PET-CT Metabolic Activity in Follicular Lymphomas" by: "C. Y. O. Wong, G. Brahmanday, M. M. Chisti, A. Muslimani, I. Jaiyesimi, P. Rigo, B.-T. Hung, P.-L. Khong, J. Huang"

Xp11.2 translocation renal cell carcinoma (TRCC) is a rare and aggressive variant of renal cell carcinoma (RCC) when presenting in adults. We report a case of a man in his early 40s who was diagnosed with stage III Xp11.2 TRCC and underwent radical nephrectomy. Seven months following the surgery, an adrenal nodule and bilateral pulmonary nodules were discovered. He underwent cryoablation of the adrenal nodule and systemic treatment with daily pazopanib. He displayed stable disease for approximately 6 years. Following this period, multiple hospitalisations interrupted daily pazopanib therapy resulting in progression of disease. His regimen was then changed to ipilimumab and nivolumab, followed by current daily therapy with axitinib. The patient now shows stable disease in his 10th year after diagnosis. This case study demonstrates the efficacy of pazopanib for metastatic Xp11.2 TRCC and warrants further investigation to supplement the guidelines regarding the use of targeted therapy for TRCC.

A label-free and reagent-free peptide mimotope capacitive biosensor has been developed for cancer drug (trastuzumab) quantification based on nonfaradic readout. The low sensitivity issue of capacitive biosensors was overcome with two innovations: peptide mimotope mixed self-assembled monolayer (SAM) biointerface and dilution of the analysis buffer. Signal amplification was achieved through dilution of phosphate-buffered saline (PBS) to tune Cdl to dominate the overall capacitance change upon target binding, which contribution is often negligible without dilution. After 1000× dilution, the limit of detection was lowered 500-fold (0.22 μg/mL) and the sensitivity was increased 20-fold [0.04192 (μg/mL)−1] in comparison with undiluted PBS. The proposed signal amplification strategy is more straightforward and practical compared to biorecognition element engineering and other strategies. The proposed method was further applied to planar electrodes for optimizing sensing response time to less than 1 min.

During induction treatment, acute myeloid leukemia patients may develop pulmonary infiltrates due to infectious or noninfectious etiologies. The risk association and the clinical outcome of such pulmonary infiltrates are poorly characterized in the literature.We retrospectively reviewed 363 cases of acute myeloid leukemia patients who received induction therapy as inpatients over a period of 11 years at William Beaumont Health System. Of these 363 patients, 120 developed pulmonary infiltrates during induction therapy, those patients were divided into 2 groups based on distribution of the infiltrate presenting as localized or diffuse in nature. Data on patients characteristics, leukemia subtype, cytogenetic risk, microorganism type, white blood cell count at diagnosis, neutrophil count at the time the infiltrate was reported, response to antibiotic and/or antifungal therapy, using respiratory support, and mortality rate were retrieved through chart review.Thirty-three percent of patients developed pulmonary infiltrates during their induction therapy. Sixty-three patients (52.5%) had a localized infiltrates and 57 patients (47.5%) had diffuse infiltrates. Of the 120 patients with pulmonary infiltrates, 48 (40%) had at least 1 pathogenic microorganism identified, and 58 (48.7%) required intubation and ventilatory support. Patients with localized pulmonary infiltrates were more likely to have positive pathogenic microorganisms (68.3% vs. 8.8%, P0.001), to be neutropenic (96.8% vs. 21%, P0.001), and tended to have potentially reversible infiltrates after treatment (87.3% vs. 21%, P0.001). Whereas patients with diffuse infiltrates were more like to require intubation (78.9% vs. 21%, P0.001), to have leukocytosis (white blood cell100 billions/L) at diagnosis (54.4% vs. 0%, P0.001), and had a higher mortality rate (70.2% vs. 9.5%, P0.001).The radiologic patterns of pulmonary infiltrates showed specific etiological and prognostic associations. Diffuse infiltrates are an unfavorable characteristic with overall dismal outcome.

Rationale: Treatment of acute myelogenous leukemia (AML) remains a challenge in elderly populations, those with comorbid conditions, and patients with poor performance status indices. The optimal choice for induction therapy as well as further agent selection is unclear, and current guidelines recommend enrollment in a controlled clinical trial. Methods: Institutional cases of AML via an electronic medical record query performed in November 2017 containing cases of AML in patients 65 years of age or greater from 01/01/2000 to 06/21/2017 were extracted. Instances of acute myelogenous leukemia were identified by ICD codes. Age, gender, induction therapy, cytogenetics, molecular analyses, and overall survival were collected. Results: A total of 61 cases of AML in patients aged 65 or greater were identified, with those having incomplete data being excluded from analysis. The mean age of included patients was 78.9 years of age, 35 were male and 26 were female. 60 confirmed deaths were recorded. 26 patients received conventional 7+3 (42.6%), 22 received a hypomethylating agent (HMA) (31.1%), 16 (26.2%) did not receive treatment. Conclusion: Our institutional data showed overall survival was significantly longer when treated with 7+3, 354 days (95% CI [93, 614]), vs. 61 days (95% CI [15, 107]). Similarly, OS was significantly longer when treated with HMA, 303 days (95% CI [23, 583]). Risk of death, accordingly, was as follows: 7+3 HR .347 (.179-.672), HMA HR .348 (.173-.703). Our institutional mortality data reasonably reflected SEER data analysis reported by Medeiros et al concerning untreated patients, but trended toward a greater OS for those treated with 7+3 or HMA. Registry data, as well as our institutional data, demonstrate a survival benefit to intensive chemotherapy and palliative chemotherapy, while controlled trials have not shown this benefit consistently in elderly populations. Practices regarding induction therapy vary greatly between institutions. Determination of which elderly patients to treat with intensive therapy remains difficult. References: Almeida AM, Ramos F. Acute myeloid leukemia in the older adults. Leuk Res Rep. 2016;6:1-7. Eleni LD, Nicholas ZC, Alexandros S. Challenges in treating older patients with acute myeloid leukemia. J Oncol. 2010;2010:943823. Medeiros BC, Satram-hoang S, Hurst D, Hoang KQ, Momin F, Reyes C. Big data analysis of treatment patterns and outcomes among elderly acute myeloid leukemia patients in the United States. Ann Hematol. 2015;94(7):1127-38. Disclosures Chisti: Eli Lilly: Speakers Bureau; Medscape: Honoraria; UpToDate: Honoraria.

A patient with a diagnosis of myelodysplastic syndrome (MDS) with isolated 5q deletion underwent repeat bone marrow biopsy to assess haematological response after 6 months of initial lenalidomide therapy. Subsequent bone marrow biopsies revealed persistent MDS with del(5q) in addition to a small atypical mast cell population with >25% of mast cells with spindle-shaped morphology and immunohistochemistry characteristics consistent with mastocytosis. Molecular testing on the bone marrow was positive for cKIT D816V and the patient was diagnosed with systemic mastocytosis (SM) with an associated haematological neoplasm. MDS with SM is well known to be associated; however, to the best of our knowledge, only one prior case report identifies MDS with del(5q) and associated cKIT D816V positive mastocytosis. While the exact clonal origin of both chromosomal aberrations is unclear, this case illustrates the therapeutic efficacy of lenalidomide in a patient with MDS with del(5q) and rarely associated cKIT positive SM.

Extrapulmonary small cell carcinomas (SCCs) are rare and often have an aggressive natural course. A 42-year-old female presented to the hospital with vaginal bleeding and lower abdominal pain. She was eventually diagnosed with SCC of cervix by biopsy. She was treated with chemoradiation. However, on follow-up positron emission tomography (PET) scan, fluorodeoxyglucose (FDG) uptake was noted in bilateral breasts. Biopsy of these lesions was consistent with metastatic SCC. Breast is a very unusual site for metastasis of cervical SCC and only four cases have been reported in the medical literature to date. Our case highlights the importance of considering metastatic disease when evaluating breast mass in patients with history of SCC of cervix. World J Oncol. 2015;6(1):301-303 doi: http://dx.doi.org/10.14740/wjon858w

We describe our experience of the case of a young female who presented with chest pain and was found to have an intra-pericardial mass that was later confirmed to be a paraganglioma. Although preoperative magnetic resonance imaging (MRI) did not show any left atrial invasion, the patient died in the peri-operative period due to irreparable damage of the cardiac structures from extensive neoplastic invasion. We then performed a retrospective analysis of the available literature to find the factors associated with adverse surgical and long-term outcomes in patients with cardiac paraganglioma.We found 93 case reports of cardiac and/or pericardial paragangliomas in the literature. After exclusions, 82 cases were included in the final analysis. The patients were divided into two groups based on the outcome of surgical management. Univariate analysis was performed using SPSS software (Chicago, IL version 18), and the statistical significance was defined as a p-value0.05.The comparison of available demographic, clinical, pathological and laboratory parameters between the deceased and the surviving patients revealed that only the intra-cardiac location (p-value=0.021) and the development of metastases (p-value0.001) were independently associated with increased surgical and long-term mortality, respectively. The size of a paraganglioma, its functional status or invasion into the surrounding structures does not appear to affect short-or long-term survival in these patients. The Kaplan-Meier survival curve showed excellent long-term prognosis for patients with a complete surgical removal of the neoplasm. Based on our experience, we also suggest preoperative imaging with a three dimensional cardiac CT and evaluation for cardiac transplantation before embarking on the surgical resection of these tumors.

Acute promyelocytic leukemia (APL) with the unique t(15;17) translocation has a high complete remission and disease-free survival rates following chemotherapy with all-trans-retinoic acid. Chemotherapy complications including secondary malignancies are rare. In this report we present therapy-related T-lymphoblastic lymphoma following APL treatment. The bone marrow analysis showed MLL and MAML2 genes rearrangement that can explain the molecular basis for the lymphoma development.

Cancer-associated retinopathy (CAR) is an uncommon paraneoplastic retinopathy usually associated with small cell lung carcinoma. To our knowledge, there is no previous report in the English literature of CAR syndrome occurring in lymphoma patients. We describe a rare case of CAR syndrome in a 62-year-old male with non-Hodgkin’s lymphoma (NHL) treated with four doses of intravenous immunoglobulin.

Dear Editor, A 66-year-old female was diagnosed in 2000 with hairy cell leukemia (HCL). Flow cytometry from her bone marrow biopsy (BMB) demonstrated a monotypic B cell population expressing CD11c, CD22, CD25, and CD103. She was successfully treated with cladribine [1]; however, in 2003, she relapsed, and BMB showed a monotypic B cell population. Cytogenetic analysis revealed an abnormal hyperdiploid karyotype in 2 of 20 metaphase cells: 48,XX,+4,del(6)(q23), del(8)(p21)x2,+12,del(14)(q24), add(17)(p13) (Fig. 1). She was again treated with cladribine and rituximab [2]. In 2008, imaging revealed splenomegaly. Splenectomywas performed, and pathology showed HCL. BMB revealed extensive involvement by a monotypic B cell population negative for CD5, CD10, CD103, and CD25. This phenotype was the same as reported on previous BMB, but differed in that it was CD25 and CD103 negative. Five months later, the patient presented with a left pyriform sinus mass (SUV of 32.8 on PET scan) which was biopsied (Fig. 2). BMB revealed involvement by the previously diagnosed HCL with a monoclonal B cell population demonstrating a phenotype similar to that observed in previous studies. Based on histologic and immunophenotypic findings, this tumor was classified as Langerhans/dendritic cell sarcoma (L/DCS) (expression S100, CD1a; negative for B and T cell markers and CD30). Cytogenetic evaluation identified the hyperdiploid complex karyotype: 47,XX,+4,del(6)(q23),del(8)(p21)x2,+12, -13,del(14)(q24),add(17)(p13). This karyotype and the one obtained in 2003 BMB positive for HCL were essentially identical, although L/DCS presented with monosomy 13. In addition, clonal immunoglobulin gene rearrangements identified by polymerase chain reaction from both specimens were also identical. Combined, cytogenetic, and immunoglobulin gene rearrangement studies suggest that both the HCL and L/DCS developed from the same precursor cells. The patient was treated with three cycles of gemcitabine and docetaxel [3]. However, due to significant progression, the patient opted for hospice. Clinical data have shown that two hematopoietic populations in the same patient may share identical genetic changes or abnormalities, raising the possibility that tumors expressing the phenotype of one hematopoietic lineage might “transdifferentiate” into a genetically similar but phenotypically distinct tumor of a different lineage [4]. Histiocytic/dendritic cell sarcomas (H/DCS) arising from follicular lymphoma (FL) have been reported earlier (eight patients) [5]. In six of these patients, both lesions possessed the same genetic aberration, namely the FL-associated IGH/BCL2 gene rearrangement associated with the t(14;18)(q32;q21). The remaining two demonstrated identical BCL2/JH or clonal IGH gene rearrangements or both. Based on these observations, the authors suggested a clonal relationship between FL and H/DCS. Feldman et al. also demonstrated a common clonal origin in a patient with acute lymphoblastic leukemia and subsequent histiocytic sarcoma, based on identical IGH and TCRγ gene rearrangements in both lesions [6]. Zhang et al. described a Electronic supplementary material The online version of this article (doi:10.1007/s00277-011-1399-5) contains supplementary material, which is available to authorized users. A. Muslimani :M. M. Chisti (*) : I. Boxwala : I. Jaiyesimi Department of Hematology and Oncology, Oakland University William Beaumont School of Medicine, William Beaumont Hospital, 3577 W 13 Mile Rd, Suite 202, Royal Oak, MI 48073, USA e-mail: mohsinchisti@yahoo.com

e12502 Background: Her2Neu (H) antigen, expressed on 20% of Breast cancers, is an established target for antibody therapy with T. Immunohistochemistry is still the most widely used technique to detect h level which is time consuming and does not reveal any details of interaction between the molecules. We have developed a new innovative biosensor based novel technique to study real time interaction of h antigens with T using QCM Piezo-immunosensor. This quantitative label free peptide based assay can be used to characterize cell surface antigen, to study antigen- antibody interactions and obtain understanding of mechanisms of resistance. Methods: A label free and reagent free peptide mimotope capacitive biosensor is developed for T quantification based on non-Faradaic readout. The low sensitivity issue of capacitive biosensor was overcome with two innovations: peptide mimotope mixed SAM biointerface and dilution of the testing buffer. Signal amplification was achieved through dilution of the PBS buffer to tune Cdl to dominate the overall capacitance change upon target binding. After 1000 times dilution, limit of detection is lowered 500 times (0.22 µg/mL) and the sensitivity increased 20 times (0.04192 (µg/mL)-1). Results: Binding was very specific. Signal amplification strategy is practical. Further applied to planar electrode for optimizing sensing, response time in less than 1 minute. Conclusions: This is the first report of T detection using electrochemical method based on non-Faradaic impedance. h antigen density and interactions of antigens will help physicians to determine the clinical efficacy and resistance mechanisms to targeted antibodies like T and ado-Trastuzumab.For the first time, we have established a low cost, highly sensitive, fast, synthetic, QCM assay which could be used as a basis for developing a new generation of affinity-based Immunosensor assays. This real time capability and its simplicity of operation are highly suitable for multipurpose studies on living cells including cell immobilization, cytotoxicity of drugs, and the cell action mechanisms

A man in his early 40s with a history of ulcerative colitis, treated with infliximab, was diagnosed with plasmablastic multiple myeloma. He was treated with chemotherapy and stem cell transplant but developed recurrence and ultimately died from metastatic disease. Could inflammatory bowel disease or infliximab therapy have any role in development of myeloma in this young patient? The role of inflammatory bowel disease and infliximab therapy in the development of multiple myeloma is controversial but interesting and worth considering.

A 46-year-old man with a long-standing history of Crohn’s disease who was treated with multiple therapies over a period of 9 years presented with oral lesions which on biopsy demonstrated peripheral T-cell lymphoma. Initially, the development of T-cell lymphoma was presumed to be secondary to prolonged immunosuppression but it did not respond to withholding immunosuppressive therapy. On treatment with CHOP (cyclophosphamide, hydroxydaunorubicin, oncovin and prednisone) chemotherapy, complete remission was achieved. Although development of malignancies in the immune-suppressed patient with Crohn9s disease has been previously described but we present a rare case of T-cell lymphoma in a similar patient, which has not been reported before.

CD20, expressed on greater than 90% of B-lymphocytic lymphomas, is an attractive target for antibody therapy. Rituximab is a chimeric murine/human-engineered monoclonal antibody which can selectively deplete CD20-expressing cells in peripheral blood and lymphoid tissues. The immobilization of B-lymphoblast-like Burkitt's lymphoma Raji cells on the quartz crystal microbalance (QCM) gold electrode surface using arginine-glycine-aspartic acid (RGD) tripeptide was electrochemically confirmed. The real-time processes of attachment of Raji cells on the gold electrode and the subsequent binding of Rituximab to the cells were studied using a QCM biosensor. The interaction between Rituximab and Raji cells led to the increased resonant frequency shifts (Δf0) in the studied antibody concentration range from 5 to 250 μg mL(-1) following the Langmuir adsorption model. From these observations, the apparent binding constant between a single-layer of Rituximab and Raji cells was calculated to be 1.6 × 10(6) M(-1). Control experiments using other therapeutic antibodies (i.e., Trastuzumab and Bevacizumab) and different cells (i.e., T cells and endothelial cells) proved the specific interaction between Rituximab and B cells. The effects of Ca(2+) and Mn(2+) ions on the Rituximab-Raji cell interaction were also studied providing the enhanced QCM signals, in particular with Ca(2+), further indicating that CD20 is a calcium ion channel that can transport these metal ions into the cells and accelerate the cell lysis induced by Rituximab. Thus, the real time capability of QCM and its simplicity of operation are shown to be highly suitable for multipurpose studies on living cells including cell-immobilization, cytotoxicity of drugs, and the cell action mechanisms.

Background: Antigens like CD20 antigen, are established targets for antibody therapy with monoclonal antibodies (mAb) like Rituximab. Mixed clinico-pathological responses to mAb have been reported either due to presence of antibodies, rapid clearance or low density of target receptor/antigens. This demands need for an assay to monitor serum mAb therapeutic levels to ensure appropriate dosage. Enzyme-linked immunosorbent assay (ELISA) is still the most widely used technique to detect mAb level in human serum which is expensive and time consuming. Understanding properties and interactions of antigens is quintessential for developing better targeted agents and overcoming resistance. Flow cytometry is still the most widely used technique to detect CD20 level in human serum which is expensive, time consuming and does not reveal any details of interaction between the molecules. We have developed a new innovative biosensor based novel technique to not only monitor levels but also study real time interaction of antigens with antibodies using QCM Piezo-immunosensor. This quantitative label free peptide based assay can be used to characterize cell surface antigen, to study antigen- antibody interactions and obtain understanding of mechanisms of resistance to therapy. Method:Mimotope was used as a substitute for the antigen like CD20 and HER2 receptor protein in QCM assays to detect mAb level. The validation samples were prepared from the standard T solution in 10% human serum at three concentrations (10, 20 and 40 ug/ml). The changes in frequencies (ΔF) of sera from 3 female patients were obtained by calculating the differences between frequency shifts in pre and post mAb infusion. mAb level was calculated by equation, (ΔF +1.0022) ÷ 0.9997 μg / ml. The real-time processes of attachment of Cells like Raji cells on the gold electrode and the subsequent binding of antibody like Rituximab to the cells were studied using QCM biosensor. The interaction between Antigen and Antibody led to the increased resonant frequency shifts (df0) in the studied antibody concentration range from 5 to 250 μg mL-1 . Control experiments using other therapeutic antibodies (i.e., Trastuzumab and Bevacizumab) and different cells (i.e., T cells and endothelial cells) proved very specific interaction between Rituximab and CD20 antigens on B cells Results: Antigen and Antibody binding was very specific. This binding decreased the electrochemical activity and stability of the cells, supporting the cell lysis mechanisms of action of Rituximab. We showed that assay sensitivity was dependent upon the amino acids used to tether and link the peptide to the sensor surface and the buffers used. QCM assay was capable of detecting mAb like Trastuzumab serum level as low as 0.038 nM (linear operating range of 0.038-0.859 nM). The time frame of assay was 20-30 minutes. These results were in concordance with previously published results using ELISA. We have shown a systematic approach for using QCM technique to quantify the apparent binding constant between antigen and antibody can reveal antigen density. Conclusion: We have established a low cost, highly sensitive, fast, synthetic peptide based QCM assay which could be used as a basis for developing a new generation of affinity-based Immunosensor assays to monitor mAb serum levels like Rituximab, Trastuzumab and other monoclonal antibodies, helping physicians to determine the clinical efficacy of these drugs and ensuring appropriate dosages. Moreover antigen density and interactions of antigens with respective monoclonal antibodies like CD20 with Rituximab will help physicians to determine the clinical efficacy and resistance mechanisms to targeted antibodies like Rituximab and Ofatumumab. This could be used as a basis for developing a new generation of affinity-based Immunosensor assays. Our study shows that peptide mimotopes have potential benefit in sensor applications as the peptide-peptide interactions in the peptide mimotopes could be manipulated by the addition of functional groups to the peptide to influence binding of the target protein as well as for surface immobilization. Disclosures No relevant conflicts of interest to declare.

Patients with diffuse large B cell lymphoma can occasionally develop hypercalcemia but it is rare at the onset of disease. We present a case of an elderly female who presented with refractory hypercalcemia, workup of which led to the diagnosis of B cell lymphoma. We discuss about various etiologies for development of hypercalcemia in a patient with lymphoma or leukemia.

Therapeutic antibodies are antigenically similar to human antibodies and are difficult to detect in assays of human serum samples without the use of the therapeutic antibody's complementary antigen. Herein for the first time, we established a platform to detect Herceptin in solutions by using a small (2.2 kDa), inexpensive, highly stable human epidermal growth factor receptor (HER2) mimotope-derived synthetic peptide immobilized on the surface of a Au quartz electrode. We used the HER2 mimotope as a substitute for the HER2 receptor protein in piezoimmunosensor or quartz crystal microbalance (QCM) assays to detect Herceptin in human serum. We demonstrated that assay sensitivity was dependent upon the amino acids used to tether and link the peptide to the sensor surface and the buffers used to carry out the assays. The detection limit of the piezoimmunosensor assay was 0.038 nM with a linear operating range of 0.038-0.859 nM. Little nonspecific binding to other therapeutic antibodies (Avastin and Rituxan) was observed. Levels of Herceptin in serum samples obtained from treated patients, as ascertained using the synthetic peptide-based QCM assay, were typical for those treated with Herceptin. The findings of this study are significant in that low-cost synthetic peptides could be used in a QCM assay, in lieu of native or recombinant antigens or capture antibodies, to rapidly detect a therapeutic antibody in human serum. The results suggested that a synthetic peptide bearing a particular functional sequence could be applied for developing a new generation of affinity-based immunosensors to detect a broad range of clinical biomarkers.

Tumor lysis syndrome (TLS) is an oncology emergency that occurs as a result of rapid tumor cell breakdown and the consequent release of massive amounts of intracellular contents, including potassium, phosphate, and uric acid, into the systemic circulation. These metabolic disturbances lead to life-threatening conditions and may cause sudden death if not treated. TLS commonly occurs following initiation of cytotoxic treatment in patients with high-grade lymphomas or acute lymphoblastic leukemia. Spontaneous cases involving both solid and hematologic tumors have also been reported. Rarely, TLS occurs following treatment with irradiation, corticosteroids, hormonal therapy, or biologic therapy. It is necessary to identify patients at risk for TLS early in order to initiate preventive measures. In the event that preventive measures fail, the clinical parameters and signs of TLS must be understood and recognized so that treatment can begin as soon as possible, as this condition is a significant cause of morbidity and mortality.

Background: CD20 antigen, expressed on greater than 90% of B-cell lymphomas, is an established target for antibody therapy with monoclonal antibodies like Rituximab, which can selectively deplete CD20-expressing cells in peripheral blood and lymphoid tissues. Understanding properties and interactions of CD20 antigens is quintessential for developing better targeted agents and overcoming resistance. It has not been clearly established yet whether CD20 antigen density corresponds with response to Rituximab. Flow cytometry is still the most widely used technique to detect CD20 level in human serum which is expensive, time consuming and does not reveal any details of interaction between the molecules. We have developed a new innovative biosensor based novel technique to study real time interaction of CD20 antigens with Rituximab using QCM Piezo-immunosensor. This quantitative label free peptide based assay can be used to characterize cell surface antigen, to study antigen- antibody interactions and obtain understanding of mechanisms of resistance to therapy. Method: The immobilization of Raji cells on the QCM gold electrode surface using RGD tripeptide was electrochemically confirmed (Figure 1). The real-time processes of attachment of Raji cells on the gold electrode and the subsequent binding of Rituximab to the cells were studied using QCM biosensor. The interaction between Rituximab and Raji cells led to the increased resonant frequency shifts (df0) in the studied antibody concentration range from 5 to 250 μg mL-1 following the Langmuir adsorption model (Figure 2). From these observations, the apparent binding constant between a single-layer of Rituximab and Raji cells was calculated to be 1.6×106 M-1 (Figure 3). Control experiments using other therapeutic antibodies (i.e., Trastuzumab and Bevacizumab) and different cells (i.e., T cells and endothelial cells) proved very specific interaction between Rituximab and CD20 antigens on B cells. Calcium and Manganese ions were added to the cell culture and corresponding responses by QCM were monitored. Results: CD20 binding with Rituximab was very specific. This binding decreased the electrochemical activity and stability of the cells, supporting the cell lysis mechanisms of action of Rituximab. We have shown a systematic approach for using QCM technique to quantify the apparent binding constant between Raji cells and Rituximab which can reveal CD20 antigen density. Moreover, increased QCM responses were found in the presence of Ca2+ ions and high concentration Mn2+ ions, supporting the function of CD20 as a calcium ion channel. Microscopic inspection proved that increased Ca2+ ions could promote the Rituximab binding and cell lysis induced by Rituximab, which was not seen with Manganese. Conclusion: CD20 antigen density and interactions of CD20 antigens with respective monoclonal antibodies will help physicians to determine the clinical efficacy and resistance mechanisms to targeted antibodies like Rituximab and Ofatumumab. For the first time, we have established a low cost, highly sensitive, fast, synthetic, QCM assay which could be used as a basis for developing a new generation of affinity-based Immunosensor assays. This real time capability of QCM and its simplicity of operation are highly suitable for multipurpose studies on living cells including cell immobilization, cytotoxicity of drugs, and the cell action mechanisms. Figure 1 Figure 1. Figure 2 Figure 2. Figure 3 Figure 3. Disclosures No relevant conflicts of interest to declare.

We report a rare case of haemorrhagic colitis attributed to dasatinib therapy in a 47-year-old African-American woman who was diagnosed with extramedullary T-lymphoblastic transformation of chronic myeloid leukaemia. The patient received intensive chemotherapy and dasatinib 100 mg/day. After achieving complete cytogenetic and major molecular response after 9 months of therapy, she developed bloody diarrhoea and pancytopenia. Colonoscopy showed inflammation of the descending colon and histopathology revealed patchy increase in intraepithelial lymphocytes. Dasatinib was stopped with prompt resolution of diarrhoea. The current literature suggests that there is an association in a subset of patients on dasatinib between clonal T-cell lymphocytosis in the peripheral blood and developing colitis and pleural effusions. These patients had a good response to dasatinib as did our patient. Our patient illustrates a unique disease presentation along with a rare drug adverse event.

1541 Background: Worldwide ethnic variations in the distribution of BRCA1 and BRCA2 mutations of breast cancer patients have been recently recognized. This has led to investigations of the epidemiology, genetics and clinical characteristics of BRCA positive individuals within specific populations. This study aims to describe the findings of BRCA genetic testing in a cohort of Arab American women. Methods: A total of 73 women of Arab ancestry were evaluated in the Beaumont Cancer Genetics Program from Jan 2008 to Jan 2013. Criteria for genetic testing included a personal or family history suggestive of Hereditary Breast and Ovarian Cancer Syndrome (HBOC). Patients underwent comprehensive genetic counseling, followed by full sequence analysis for germline mutations in BRCA1 and BRCA2. Results: 63 women of Arab ancestry underwent genetic testing for BRCA1 and BRCA2. 13 (21%) patients were found to be mutation carriers, of whom 10 (16%) of the 63 had deleterious mutations (7 in BRCA2, and 3 in BRCA1), and 3 (5%) had variants of undetermined significance (VUS) in BRCA2. Of the 10 patients with deleterious mutations, 4 (40%) unrelated individuals had the same mutation, 5804del4, in exon 11 of BRCA2. The remaining patients had deleterious mutations in exon 2, exon 20, and exon 13 of BRCA2; one patient had a BRCA1 and BRCA2 mutation (exon 18). 7 of 10 patients with deleterious mutations had a cancer diagnosis, of which 5 had breast cancer, 1 had ovarian cancer, 1 had pancreatic cancer, and 3 were unaffected. Conclusions: This study demonstrates that BRCA mutations (predominantly in BRCA2) were seen in a significant proportion of Arab American women undergoing genetic testing for HBOC. A mutation in BRCA2, 5804del4, was seen in nearly half (4/10) of the carriers of deleterious mutations. This mutation, in exon 11, has not previously been associated with Arab ethnicity and may represent a founder mutation. Knowledge of the genetic spectrum, frequency, and clinical characteristics of BRCA mutation carriers will lead to greater understanding of hereditary cancer in Arab American women.

Abstract 4319 Background: CBs are highly variable at diagnosis and during the course of IT in AML patients. Assessing response to IT carries a huge implication on the prognosis of individual patient with AML. Our study investigates whether late clearance of CBs during IT using standard cytarabine + anthracycline regimen is associated with refractory phenotype. Methods: We retrospectively reviewed the chart of 83 AML patients (43 males, 40 females, mean age 61.7) who received standard cytarabine and anthracycline regimen during induction between January, 2000-January, 2011 at William Beaumont Health System. Data collected include complete blood count with blast count during course of induction, and bone marrow response. AML is considered refractory if morphological evaluation, flow cytometry or cytogenetic study was positive in the first bone marrow post induction. Response to IT was assessed according to Cancer and Leukemia Group B (CALGB) criteria as complete remission versus residual leukemia or treatment failure (failing to achieve complete remission). Results: We noted that 57 of 83 patients (68.7%) showed CBs at the time of diagnosis. During the IT, CBs clearance occurred within 7 days (early clearance) in 38 of these 57 patients. The remaining 19 patients had CBs persistent more than 7 days (delayed clearance). The frequency of bone marrow residual disease at count recovery post IT was significant higher in patients with late clearance and those with early clearance (84% vs 42%, p=0.0015). Further analysis of data showed the frequency of bone marrow residual disease was not significantly different between patients with no CBs at the diagnosis and those with early clearance of CBs (38% vs 42%, p=0.8). Conclusion: Adult AML patients with persistent CBs >7 days during IT with standard induction cytarabine and anthracycline regimen are more likely to have induction failure. CBs clearance can be used as an early assessment of response to the IT. Disclosures: No relevant conflicts of interest to declare.

628 Background: Varied clinico-pathological response to monoclonal antibodies like T has been reported either due to presence of antibodies, rapid clearance or low density of target receptor/antigens. This demands need for an assay to monitor serum T therapeutic levels to ensure appropriate dosage. Enzyme-linked immunosorbent assay (ELISA) is still the most widely used technique to detect T level in human serum which is expensive and time consuming. For the first time, we established a platform to detect T level by using a small (

Abstract 3148 Background: VTEs are common complications in association with IT which may cause additional morbidity and mortality in AML patients. However, treating patients with AML is challenging because of the cytopenias due to chemotherapy and the high risk for bleeding during IT. This study investigates frequency, risk factors, and safety of using anticoagulation (AC) therapy for VTEs during IT. Method: We retrospectively reviewed the charts of AML patients who received IT between January, 2000-January, 2011 at William Beaumont Health Systems. Exclusion criteria included a documented personal history of inherited thrombophilia. Data retrieved included the following: patient characteristics, leukemia subtype, cytogenetic risk, location of the VTEs, FLT3 mutations, IT regimen used (cytarabine and anthracycline regimens or hypomethylating agents), AC therapy, bleeding complications, mortality related to AC therapy. All patients who received AC were initially treated with regular intravenous unfractionated heparin or subcutaneous low molecular weight heparin. Patients were subsequently started on oral warfarin during the first 10 days of the initial treatment with a targeted INR of 2.0–3.0. Results: We found 48 of 363 (13.2%) AML patients developed VTEs during IT. Of those patients, 56.3 % were female. The VTEs occurred most frequently in upper extremities (58%) and were catheter-related. Other locations for VTEs included lower extremities (21%), pulmonary embolism (15%), and mesenteric or portal veins (6%). We note that 41 patients (87%) received AC therapy. Of these, three patients (7.3%) had bleeding complications and no AC therapy-related deaths were observed. When the three cytogenetic risk groups were compared, there was no difference in the incidence of VTEs (good vs intermediate vs poor). Patients with FLT 3 mutations, however, had a significant higher incidence of VTEs when compared to patients without FLT3 mutations (55.3% vs 12% p Conclusions: We found that 13% of AML patients developed VTEs during IT, most commonly in upper extremities and were catheter-related. The risk for VTEs was markedly increased in patients with FLT3 mutations. Furthermore, using a cytarabine + anthracycline regimens carried a higher risk for VTEs when compared to regimens using a hypomethylating agents. Finally, using AC therapy during IT is relatively safe and is associated with low risk of bleeding complications. Disclosures: No relevant conflicts of interest to declare.

Abstract 2087 Background: During IT, AML patients may develop PI due to infection, leukostasis, pneumonitis, drug reaction or even acute respiratory distress syndrome. The risk association and the clinical outcome of such PI are poorly characterized in the literature. This study investigates the frequency, radiologic patterns, and outcome of PI during the IT of AML patients. Methods: We retrospectively reviewed 363 cases of AML patients who received IT either cytarabine and anthracycline regimens, or hypomethylating agents between January, 2000-January, 2011 at William Beaumont Health System. Of 363 patients, 120 developed PI during IT, those patients were divided into 2 groups based on distribution of the infiltrate presenting whether localized or diffuse infiltrate. Distribution of the infiltrate was evaluated by dividing the thorax vertically in the midline, then horizontally by two lines originating above and below the hilus resulting in six areas. Localized infiltrate was defined as involvement of 1–3 areas, and diffuse infiltrate was defined as >3 areas were involved. Detected by either Bronchioalveolar lavage culture or sputum culture revealing a pathogen other than coagulase-negative staphylococci or corynebacteria was considered as pathogenic microorganisms. Treatment end points were defined as resolve or persistence of the infiltrate or death. Data on pts characteristics, leukemia subtype, cytogenetic risk, microorganism type, white blood cell count (WBC) at diagnosis, neutrophils count at the time of the infiltrate reported, response to antibiotic and/or antifungal therapy, using respiratory support, mortality rate, were retrieved from the records. Results: Our study involved 120 patients. Of these, 33% developed PI during their IT. This population was 53.3 % female, median age 66 years (range 23–93). We noted that 63 patients (52.5%) had localized infiltrate and 57 patients (47.5%) had diffuse infiltrate. Of the 120 patients, 46 (39.3%) had pathogenic microorganisms. These microorganisms were found to be 50% gram positive, 32% gram negative, 10.8% fungal, and 4.3% anaerobic. All 120 patients received two broad-spectrum antibiotics and/or an antifungal. Of the total number of patients, 58 (48.7%) required intubation and ventilatory support. The repeat computed tomography at the end of the hospital stay (after the treatment) showed resolution of the infiltrate in 67 patients (55.8%). During our study, 46 patients died from PI (38.3 %). Further analysis of the data showed patients with localized PI (when compared to patients with diffuse infiltrate) were more likely to have positive pathogenic microorganisms (68.3% vs 8.8%, p Patients with diffuse infiltrate (when compared to patients with localized infiltrate) were more like to require intubation (78.9% vs 21%, p 100 Bil/L) at diagnosis (54.4% vs 0%, p Conclusions: During IT about one third of the AML patients developed PI. The radiological patterns of PI showed specific etiological and prognostic associations, may guide the clinical decision making processes. Diffuse PI is an unfavorable characteristic with overall dismal outcome. Disclosures: No relevant conflicts of interest to declare.

Abstract 3936 Deacetylases (DACs) are enzymes that remove the acetyl groups from target proteins [histones (class I) and non-histone proteins (class II)], leading to regulation of gene transcription and other cellular processes. Panobinostat (LBH589) is a novel and potent DAC class I and II inhibitor undergoing pre-clinical and clinical testing. In order to better characterize the role of DAC inhibitors in the treatment of refractory/resistant B-cell lymphoma., We studied the anti-tumor activity of panobinostat as a single agent or in combination with the proteasome inhibitor (BTZ) against a panel of rituximab-[chemotherapy]-sensitive cell lines (RSCL), rituximab-[chemotherapy]-resistant cell lines (RRCL), and primary lymphoma cells isolated from patients with treatment-naïve or refractory/relapsed B-cell lymphoma. In addition, we characterized the mechanisms responsible for panobinostat anti-tumor activity. Non-Hodgkin lymphoma (NHL) cell lines were exposed to escalating doses of panobinostat (0.5-5nM) +/− BTZ (1-5nM). Changes in mitochondrial potential and ATP synthesis were determined by alamar blue reduction and cell titer glo luminescent assays, respectively. Subsequently, protein lysates were isolated from panobinostat +/− BTZ exposed cells and changes in members of Bcl-2 family proteins were evaluated by Western blot. Finally, to characterize panobinostat's mechanisms-of-action, lymphoma cells were exposed to panobinostat with or without pan-caspase (Q-VD-OPh, 5mM) or autophagy (3-methyladenine [3MA] 5mM) inhibitors and changes in cell viability were detected as above. Optimal experimental conditions were confirmed by Western blot. Panobinostat exhibited dose-dependent activity as a single agent against RSCL, RRCL and patient-derived primary tumor cells (N=25). In addition, synergistic activity was observed by combining panobinostat with BTZ in vitro. The pharmacological interactions between panobinostat and proteasome inhibitor could be explained in part by the effects each agent has on the expression levels of Bcl-2 family members. In vitro exposure of lymphoma cells to panobinostat resulted in Bcl-XL down-regulation, whereas BTZ exposure causes up-regulation of Bak and Noxa and downregulation of Mcl-1 and Bcl-XL. Caspase inhibition diminished panobinostat anti-tumor activity in RSCL but not in RRCL. On the other hand, exposure of RRCL to 3MA, significantly inhibited the anti-tumor activity of panobinostat in RRCL. Together this data suggest that, panobinostat has a dual mechanism-of-action and can induce cell death by caspase-dependent and -independent pathways. Our data suggests that panobinostat as a single agent is active against rituximab-chemotherapy sensitive and resistant lymphoma cells and potentiates the anti-tumor activity of a proteasome inhibitor (BTZ). A better understanding in the molecular events (caspase-dependent and -independent) triggered by panobinostat in combination with proteasome inhibition is important in order to develop optimal combination strategies using these exciting agents in future clinical trials. (Research, in part, supported by a NIH grant R01 CA136907-01A1 awarded to Roswell Park Cancer Institute) Disclosures: No relevant conflicts of interest to declare.

Breast carcinoma is the second commonest cancer in women after non-melanoma skin cancers and, excluding melanoma, the most common tumor to metastasize to the skin in women. Cutaneous metastasis from breast cancer has varied presentations but there is no well-established classification which includes them all.We report a 69 year-old lady with advanced primary ductal carcinoma of right breast (cT4cN1cM0) who presented five months after radical mastectomy with very extensive cutaneous metastases in absence of distant spread. Skin involvement was in the form of nodules and purpuric papulo-vesicles on a background of erythema which clinically mimicked lymphatic malformation. We also propose a morphological classification of the cutaneous metastasis from breast cancer.Breast Carcinoma, Cutaneous metastasis, lymphatic malformation.

Abstract 5098 Introduction: Follicular Lymphoma (FL) comprises of 20–30% of Non-Hodgkin's Lymphomas. It is the most common lymphoma with varied clinical aggressiveness, depending on morphological grading on histology. The prognosis of FL is heterogeneous. Therefore therapeutic options for FL are increasingly becoming more risk-adopted. Pathologically, FL has been graded into grade 1–2 (FL1–2) and grade 3 (FL3) by visual counting or estimating the absolute number of centroblasts in neoplastic follicles. Recent studies found that the average tumor cell size of FL is highly variable, but is consistently reproducible, achieved by an objective measurement using flow cytometry. A significant variation in metabolic activity has also been observed in FL studied by PET scan. The purpose of this study was to investigate a new risk stratification method for FL using a combined criterion of Flow cytometry based cell size of FL cells and metabolic activity based on FDG PET scan to further evaluate their prognostic values. Materials and Methods: Retrospective study of 64 patients (25 males and 39 females with median age of 61 years), diagnosed with FL between 2006 –2010 in Beaumont Health System with proper HIC approval was performed. 44 cases were graded morphologically into low risk (FL 1–2) and 20 into high risk (FL 3), based on current WHO classification. The average tumor cell size was measured based flow cytometric analysis of the relative forward scatters (FSC) of tumor cells relative to that of internal T-cells in the lymphoma tissue. The metabolic activity was measured as in maximal standardized uptake value (SUV max) of the involved lymph node by PET scan based F-18 FDG uptake. The SUV was normalized to a glucose level of 100 using the formula: SUV100={[100 mg/dl]/[glc]}g where g=[-0. 5] from our prior publication and [Glc] was the glucose level of the patient recorded at the time of PET scan. The difference of average lymphoma cell size between grade 1–2 (FL 1–2, indolent) and grade 3 (FL 3, aggressive) was compared with Student t test. The difference of size distribution between FL with low SUV100 and FL with high SUV100 were compared with Chi square and Kappa tests. A two-tail p-value less than 0. 05 was considered significant in all tests. FSC and Metabolic activity were cross tabbed and correlated using cut off values determined by discriminant analysis. Results: The FSC of B-cells were significantly lower in low grade FL than that in high grade FL (p=0. 00002). In contrast, FSC of residual T-cells in low grade FL and high grade FL were about the same (p=0. 2). Average lymphoma cell size of the low risk group (relative FSC of −15, range of −83 to 153) was significantly smaller than that of high risk group(relative FSC of 92, range of −32 to 243), (P Conclusion: The significance of average lymphoma cell size identified by FSC in this study between FL grade 3 and grade 1–2 validate potential utility of flow cytometry in grading FL in refining the grading because the measurement of average lymphoma cell size by flow cytometry it is more reproducible, objective, and easy to use than manual counting centroblasts microscopically. Since increased metabolic activity is often associated with more aggressive clinical behavior, combining tumor cell size by flow cytometry and metabolic activity by FDG PET imaging can potentially serve as an independent criterion in risk stratification and better grading of FL. Further clinical correlation is in progress. Disclosures: No relevant conflicts of interest to declare.