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Background More than 60% of patients with lung cancer are diagnosed at advanced stages. The introduction of targeted therapies requires molecular diagnosis to guide treatment. The aim of this study was to evaluate the feasibility of performing mutational analysis with brushing specimens obtained by radial-miniprobe endobronchial ultrasound (R-EBUS) plus fluoroscopy-guided bronchoscopy in patients with peripheral pulmonary adenocarcinoma. Methods Brushing specimens were deposited on cytological slides and were conserved in Roswell Park Memorial Institute (RPMI) culture medium. DNA was isolated to perform a mutational analysis with real-time quantitative polymerase chain reaction and Sanger sequencing for epidermal growth factor receptor (EGFR) and Kirsten rat sarcoma viral oncogene homolog (KRAS). Results Thirty patients with adenocarcinoma were prospectively included. In 100% of the patients, the molecular study was viable with brushing specimens. In 16 (53.3%), KRAS or EGFR mutations were detected: 10 KRAS mutations (33.3%) and 6 EGFR mutations (20%). In a comparison with histological samples, a correlation of 86.6% was detected, and only 2 patients with wild-type results from brushing specimens presented with an EGFR mutation in histological samples. Conclusions Brushing specimens conserved in RPMI medium and obtained by R-EBUS plus fluoroscopy-guided bronchoscopy are valid for molecular studies. They allow the detection of EGFR/KRAS mutations in patients with peripheral adenocarcinoma. In addition, invasive techniques are avoided, the risk of complications is reduced, and the obtained samples are optimized.

Introduction Chemotherapy is the principal treatment in metastatic colorectal cancer (mCRC) patients. RAC1b, a RAC1 spliced variant, is over-expressed in colorectal cancer (CRC), and impairs apoptosis by activation of nuclear-factor-KB. Since RAC1b has been associated with the BRAF V600E mutation, associated with poor prognosis in CRC, we evaluated the role of RAC1b expression as a predictor of chemotherapy efficacy in mCRC. Methods We analysed KRAS and BRAF mutation, microsatellite instability and RAC1b expression in 157 mCRC patients treated with FOLFOX/XELOX in first-line therapy. Results KRAS mutations were detected in 46 patients (34%), 10 patients were BRAF mutant (7%) and 79 were WT for both, KRAS and BRAF (59%). RAC1b overexpression was found in 30 patients (19%). In the multivariate analysis, BRAF mutational status was a poor prognostic factor for overall survival (OS); hazard ratio (HR), 2.78 (95% confidence interval (CI), 1.35–5.72; p =0.0057). RAC1b overexpression was a poor survival factor for OS (HR, 2.35; 95% CI, 1.2–4.59; p =0.01) and progression-free survival (PFS) (HR, 2.4; 95% CI, 1.2–4.78; p =0.01) in KRAS/BRAF WT mCRC patients. Conclusions RAC1b overexpression constitutes a marker of poor prognosis in KRAS/BRAF WT mCRC patients treated with first-line FOLFOX/XELOX therapy.

Although receiving adjuvant chemotherapy after radical surgery, a disappointing proportion of patients with colorectal cancer will develop tumor recurrence. Probability of relapse is currently predicted from pathological staging, there being a need for additional markers to further select high-risk patients. This study was aimed to identify a gene-expression signature to predict tumor recurrence in patients with Stages II and III colon cancer treated with 5'fluoruracil (5FU)-based adjuvant chemotherapy. Two-hundred and twenty-eight patients diagnosed with Stages II-III colon cancer and treated with surgical resection and 5FU-based adjuvant chemotherapy were included. RNA was extracted from formalin-fixed, paraffin-embedded tissue samples and expression of 27 selected candidate genes was analyzed by RT-qPCR. A tumor recurrence predicting model, including clinico-pathological variables and gene-expression profiling, was developed by Cox regression analysis and validated by bootstrapping. The regression analysis identified tumor stage and S100A2 and S100A10 gene expression as independently associated with tumor recurrence. The risk score derived from this model was able to discriminate two groups with a highly significant different probability of tumor recurrence (HR, 2.75; 95%CI, 1.71-4.39; p = 0.0001), which it was maintained when patients were stratified according to tumor stage. The algorithm was also able to distinguish two groups with different overall survival (HR, 2.68; 95%CI, 1.12-6.42; p = 0.03). Identification of a new gene-expression signature associated with a high probability of tumor recurrence in patients with Stages II and III colon cancer receiving adjuvant 5FU-based chemotherapy, and its combination in a robust, easy-to-use and reliable algorithm may contribute to tailor treatment and surveillance strategies.

Purpose: Lynch syndrome accounts for 2-4% of all colorectal cancer, and is mainly caused by germline mutations in the DNA mismatch repair genes. Our aim was to characterize the genetic mutation responsible for Lynch syndrome in an extensive Colombian family and to study its prevalence in Antioquia. Methods: A Lynch syndrome family fulfilling Amsterdam criteria II was studied by immunohistochemistry and by multiplex ligation-dependent probe amplification (MLPA). Results were confirmed by additional independent MLPA, Southern blotting, and sequencing. Results: Index case tumor immunohistochemistry results were MLH1-, MSH2+, MSH6+, and PMS2-. MLPA analysis detected a duplication of exons 12 and 13 of MLH1. This mutation was confirmed and characterized precisely to span 4219 base pairs. Duplication screening in this family led to the identification of six additional carriers and 13 noncarriers. We also screened 123 early-onset independent colorectal cancer cases from the same area and identified an additional unrelated carrier. CONCLUSION:: A novel duplication of exons 12 and 13 of the MLH1 gene was detected in two independent Lynch syndrome families from Colombia. A putative founder effect and prescreening Lynch syndrome Antioquia families for this specific mutation before thorough mismatch repair mutational screening could be suggested. © 2011 Lippincott Williams and Wilkins.

By transactivacion, phosphorylated insulin growth factor receptor I (IGF-1R) can activate epidermal growth factor receptor (EGFR). MMP-7, produced by colorectal cancer cells, also can activate IGF-1R by degrading IGFBP-3 and releasing IGF-I.A cohort of patients (pts) with advanced colorectal cancer (CRC), under second- or third-line treatment with cetuximab or panitumumab, was tested using immunohistochemistry for expression of the activated form of IGF-1R (p-IGF-1R) and MMP-7. KRAS and BRAF mutation status was determined by sequencing and allelic discrimination analysis, respectively. Analyses were performed in primary CRC tumor samples or metastases, and the association of immunohistochemistry findings, mutational results, and treatment outcomes was investigated in both univariate and multivariate analyses.Expression of activated IGF-1R and MMP-7 was observed in 51 and 49% of pts, respectively. Co-expression of MMP-7 and pIGF-1R (double positivity, DP) was observed in 28 pts (25%). There was no association between KRAS or BRAF mutational status and DP (p=0.52). Pts with DP responded more poorly to first-line chemotherapy (p=0.005) and to anti-EGFR treatment (p=0.01) than non-DP pts. In wild type (WT) KRAS pts, those with DP have poorer PFS (2.7 months vs. 3.5m, p=0.036; HR 1.98, 95% CI 1.05-3.75) and OS (6.4 months vs. 8.6 m, p=0.010; HR 2.33, 95%CI 1.23-4.43) in the adjusted multivariate analysis.Our study suggests that concomitant expression of MMP-7 and activation of p-IGF-1R (DP) correlates with poor prognosis in WT KRAS pts treated with anti-EGFR.

Purpose: Early-onset colorectal cancer (CRC) is suggestive of a hereditary predisposition. Lynch syndrome is the most frequent CRC hereditary cause. The MUTYH gene has also been related to hereditary CRC. A systematic characterization of these two diseases has not been reported previously in this population. Experimental Design: We studied a retrospectively collected series of 140 patients ≤50 years old diagnosed with nonpolyposis CRC. Demographic, clinical, and familial features were obtained. Mismatch repair (MMR) deficiency was determined by microsatellite instability (MSI) analysis, and immunostaining for MLH1, MSH2, MSH6, and PMS2 proteins. Germline MMR mutations were evaluated in all MMR-deficient cases. Tumor samples with loss of MLH1 or MSH2 protein expression were analyzed for somatic methylation. Germline MUTYH mutations were evaluated in all cases. BRAF V600E and KRAS somatic mutational status was also determined. Results: Fifteen tumors (11.4%) were MSI, and 20 (14.3%) showed loss of protein expression (7 for MLH1/PMS2, 2 for isolated MLH1, 3 for MSH2/MSH6, 7 for isolated MSH6, and 1 for MSH6/PMS2). We identified 11 (7.8%) germline MMR mutations, 4 in MLH1, 1 in MSH2, and 6 in MSH6. Methylation analysis revealed one case with somatic MLH1 methylation. Biallelic MUTYH mutations were detected in four (2.8%) cases. KRAS and BRAF V600E mutations were present in 39 (27.9%) and 5 (3.6%) cases, respectively. Conclusions: Loss of MSH6 expression is the predominant cause of MMR deficiency in early-onset CRC. Our findings prompt the inclusion of MSH6 and MUTYH screening as part of the genetic counseling of these patients and their relatives. Clin Cancer Res; 16(22); 5402–13. ©2010 AACR.

BackgroundColorectal cancer (CRC) multiplicity has been mainly related to polyposis and non-polyposis hereditary syndromes. In sporadic CRC, aberrant gene promoter methylation has been shown to play a key role in carcinogenesis, although little is known about its involvement in multiplicity. To assess the effect of methylation in tumor multiplicity in sporadic CRC, hypermethylation of key tumor suppressor genes was evaluated in patients with both multiple and solitary tumors, as a proof-of-concept of an underlying epigenetic defect.Methodology/principal findingsWe examined a total of 47 synchronous/metachronous primary CRC from 41 patients, and 41 gender, age (5-year intervals) and tumor location-paired patients with solitary tumors. Exclusion criteria were polyposis syndromes, Lynch syndrome and inflammatory bowel disease. DNA methylation at the promoter region of the MGMT, CDKN2A, SFRP1, TMEFF2, HS3ST2 (3OST2), RASSF1A and GATA4 genes was evaluated by quantitative methylation specific PCR in both tumor and corresponding normal appearing colorectal mucosa samples. Overall, patients with multiple lesions exhibited a higher degree of methylation in tumor samples than those with solitary tumors regarding all evaluated genes. After adjusting for age and gender, binomial logistic regression analysis identified methylation of MGMT2 (OR, 1.48; 95% CI, 1.10 to 1.97; p = 0.008) and RASSF1A (OR, 2.04; 95% CI, 1.01 to 4.13; p = 0.047) as variables independently associated with tumor multiplicity, being the risk related to methylation of any of these two genes 4.57 (95% CI, 1.53 to 13.61; p = 0.006). Moreover, in six patients in whom both tumors were available, we found a correlation in the methylation levels of MGMT2 (r = 0.64, p = 0.17), SFRP1 (r = 0.83, 0.06), HPP1 (r = 0.64, p = 0.17), 3OST2 (r = 0.83, p = 0.06) and GATA4 (r = 0.6, p = 0.24). Methylation in normal appearing colorectal mucosa from patients with multiple and solitary CRC showed no relevant difference in any evaluated gene.ConclusionsThese results provide a proof-of-concept that gene promoter methylation is associated with tumor multiplicity. This underlying epigenetic defect may have noteworthy implications in the prevention of patients with sporadic CRC.

3553 Background: Metastatic colorectal cancer (mCRC) patients (pts), with BRAF tumor mutation (V600E) present poor overall survival (OS). RAC1b, a RAC1 spliced variant, is overexpressed in CRC, and impairs apoptosis by activation of nuclear-factor-KB. Because RAC1b and BRAF (V600E) are significantly associated in CRC (Matos et al, 2008), we evaluated if RAC1b/RAC1 mRNA expression ratio (RNA ER) was an independent prognostic factor in mCRC. Methods: We analyzed tumor samples from 186 mCRC pts, treated in first-line therapy with FOLFOX or CAPOX in three Spanish hospitals. We examined BRAF (V600E) mutational status by allelic discrimination, RAC1b/RAC1 expression ratio by mRNA RT-PCR (quantitative real time polymerase chain reaction) and mismatch repair (MMR) deficiency by microsatellite instability (MSI) analysis. We assessed whether these biomarkers were independently predictive of response rate (RR), progression free survival (PFS) or OS. Results: 88% of samples were informative for BRAF, 75% for MMR status and 85% for RAC1b/RAC1 (RNA ER). BRAF (V600E) was found in 7%, MSI-H in 5% and high >0.9-fold RAC1b/RAC1 (RNA ER) in 20% of pts. Five of 11 pts (46%) with BRAF mutation had high RAC1b/RAC1 (RNA ER) compared with 25/144 (18%) without BRAF mutation (p=0.036). All pts with BRAF mutation were MMR and none of the MSI-H pts, showed high RAC1b/RAC1 (RNA ER). Patients with low RAC1b/RAC1 (RNA ER) and BRAF WT had higher response rate (68% vs 43%; p=0.035). Response rate were not different according BRAF mutation (64% WT vs 63% mutant) (p=NS). The multivariate regression analysis identified ECOG PS (HR: 4.2 (CI 1.4-12.7) as a significant variable for PFS and LDH levels (HR: 2.26 (CI 1.3-3.8), PS (HR: 3.85 (CI 1.5-9.8) and high RAC1b/RAC1 (RNA ER) (HR: 2.6 (CI 1.1-5.9) for OS in WT BRAF pts. Conclusions: High RAC1b/RAC1 (RNA ER) constitutes a marker of poor OS and a potential marker of acquired chemo-resistance in WT BRAF mCRC pts treated with first-line oxaliplatin-based therapy.

10639 Background: To prospectively explore the role of serum MMP-7 as a predictive and prognostic marker of anti-EGFR therapy and irinotecan efficacy in third-line advanced colorectal cancer therap...

4060 Background: Single nucleotide polymorphism (SNP) in codon R497K of EGFR by reducing EGFR activity has been associated to resistance to anti-EGFR monoclonal antibodies in ACRC (Carcereny, ASCO2008). Methods: We retrospectively investigated the role of EGFR R497K and KRAS mutational status in primary CRC or metastases, in predicting response rate (RR), progression free survival (PFS) and overall survival (OS) of cetuximab or panitumumab in second or third line therapy in patients (pts) with ACRC. EGFR R497K was detected by real-time PCR using the TaqMan technology and KRAS mutation status in codons 12/13 was determined by sequencing. CT scans were done every 6–8 weeks (w) until progressive disease. Results: A total of 117 pts with available tissue out of 168 pts treated with anti-EGFR therapy in 6 Spanish Institutions, were analysed for EGFR R497K and KRAS mutational status. There were no differences in RR (18.8 vs.16.8%), PFS (13.2 vs. 12 w) and OS (31 vs. 28 w) between the whole and the selected cohort. We found no significant differences on RR (9/59;15.2 vs. 9/52; 17.3%), PFS (13.5 vs. 13.2 w) and OS (33 vs. 26.8 w) according to EGFR R497K (GG vs. GA/AA). Pts with wild-type (WT) KRAS had better response (20.7% vs. 8.1%;p=0.07) and PFS (14.4 vs. 11.7 w; p=0.006) compared with mutant KRAS. Interestingly, a significant increment on RR (30 vs. 0%, p=0.003), PFS (14.4 vs. 7.4 w, p=0.002) and OS (34.1 vs. 20 w, p=0.03) was observed only in those patients with WT KRAS and >1x upper limit of normal (ULN) lactate dehydrogenase (LDH) levels compared with mutant KRAS, but these differences were not found in pts with WT KRAS and 1xULN levels of LDH, have major benefit to anti-EGFR therapy in second-third line therapy. No significant financial relationships to disclose.

Background Colorectal cancer (CRC) is the second leading cause of cancer death in developed countries. Familial aggregation in CRC is also important outside syndromic forms and, in this case, a polygenic model with several common low-penetrance alleles contributing to CRC genetic predisposition could be hypothesized. Mucins and GALNTs (N-acetylgalactosaminyltransferase) are interesting candidates for CRC genetic susceptibility and have not been previously evaluated. We present results for ten genetic variants linked to CRC risk in previous studies (previously identified category) and 18 selected variants from the mucin gene family in a case-control association study from the Spanish EPICOLON consortium. Methods CRC cases and matched controls were from EPICOLON, a prospective, multicenter, nationwide Spanish initiative, comprised of two independent stages. Stage 1 corresponded to 515 CRC cases and 515 controls, whereas stage 2 consisted of 901 CRC cases and 909 controls. Also, an independent cohort of 549 CRC cases and 599 controls outside EPICOLON was available for additional replication. Genotyping was performed for ten previously identified SNPs in ADH1C, APC, CCDN1, IL6, IL8, IRS1, MTHFR, PPARG, VDR and ARL11, and 18 selected variants in the mucin gene family. Results None of the 28 SNPs analyzed in our study was found to be associated with CRC risk. Although four SNPs were significant with a P-value < 0.05 in EPICOLON stage 1 [rs698 in ADH1C (OR = 1.63, 95% CI = 1.06-2.50, P-value = 0.02, recessive), rs1800795 in IL6 (OR = 1.62, 95% CI = 1.10-2.37, P-value = 0.01, recessive), rs3803185 in ARL11 (OR = 1.58, 95% CI = 1.17-2.15, P-value = 0.007, codominant), and rs2102302 in GALNTL2 (OR = 1.20, 95% CI = 1.00-1.44, P-value = 0.04, log-additive 0, 1, 2 alleles], only rs3803185 achieved statistical significance in EPICOLON stage 2 (OR = 1.34, 95% CI = 1.06-1.69, P-value = 0.01, recessive). In the joint analysis for both stages, results were only significant for rs3803185 (OR = 1.12, 95% CI = 1.00-1.25, P-value = 0.04, log-additive 0, 1, 2 alleles) and borderline significant for rs698 and rs2102302. The rs3803185 variant was not significantly associated with CRC risk in an external cohort (MCC-Spain), but it still showed some borderline significance in the pooled analysis of both cohorts (OR = 1.08, 95% CI = 0.98-1.18, P-value = 0.09, log-additive 0, 1, 2 alleles). Conclusions ARL11, ADH1C, GALNTL2 and IL6 genetic variants may have an effect on CRC risk. Further validation and meta-analyses should be undertaken in larger CRC studies.