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Simple Summary: Pancreatic ductal adenocarcinoma (PDAC) is an aggressive cancer that is challenging to diagnose and treat. Current methods to measure disease burden, monitor treatment response, and predict disease progression have significant limitations. This study explores the utility of circulating neoplastic-immune hybrid cells (CHCs) as a novel blood-based biomarker. We find that pre-operative CHC levels can predict the presence of metastatic disease that may only be detected during surgical exploration, as well as identify patients who are likely to experience rapid metastatic progression after surgery. Further, CHC levels and protein expression patterns are reflective of disease response to chemotherapy. Collectively, these results suggest that CHCs could serve as crucial indicators of disease status and treatment efficacy, offering great potential to enhance survival outcomes for patients with PDAC. Background/Objectives: Pancreatic ductal adenocarcinoma (PDAC) presents significant diagnostic and prognostic challenges, as current biomarkers frequently fail to accurately stage disease, predict rapid metastatic recurrence (rPDAC), or assess response to neoadjuvant therapy (NAT). We investigated the potential for circulating neoplastic-immune hybrid cells (CHCs) as a non-invasive, multifunctional biomarker for PDAC. Methods: Peripheral blood specimens were obtained from patients diagnosed with PDAC. CHCs were detected by co-expression of pan-cytokeratin and CD45, normalized to 50,000 peripheral blood mononuclear cells. rPDAC was defined as metastatic recurrence within six months of margin-negative pancreatectomy. Cyclic immunofluorescence (CyCIF) analyses compared hybrid phenotypes in blood and tumors. Results: Blood samples were collected from 42 patients with PDAC prior to resection. Those with radiographically occult metastatic disease and rPDAC had higher preoperative CHC numbers compared to patients who did not (65.0 and 74.4, vs. 11.52 CHCs; p < 0.001). Patients with complete or near-complete pathologic responses to NAT had lower preoperative CHC numbers than partial and/or non-responders (1.7 vs. 13.1 CHCs; p = 0.008). When assessed longitudinally, those with partial pathologic response saw CHC levels become undetectable while on treatment but increase in the interval between NAT completion and resection. In contrast, patients with poor responses or development of metastatic disease experienced persistent CHC detection during therapy or rising levels prior to radiographic evidence of metastases. Further, in metastatic PDAC patients, treatment-induced phenotypic changes in hybrid cells mirrored those in paired metastatic tumor samples. Conclusions: CHC enumeration and phenotyping display promise as a real-time indicator of disease burden, recurrence risk, and treatment response in PDAC. CHCs have great potential as tumor-derived biomarkers to optimize therapeutic strategies and improve survival in patients with PDAC. [ABSTRACT FROM AUTHOR]

Significance: Head and neck squamous cell carcinoma (HNSCC) has the sixth highest incidence worldwide, with > 650,000 cases annually. Surgery is the primary treatment option for HNSCC, during which surgeons balance two main goals: (1) complete cancer resection and (2) preservation of normal tissues to ensure post-surgical quality of life. Unfortunately, these goals are not synergistic, where complete cancer resection is often limited by efforts to preserve normal tissues, particularly nerves, and reduce life-altering comorbidities., Aim: Currently, no clinically validated technology exists to enhance intraoperative cancer and nerve recognition. Fluorescence-guided surgery (FGS) has successfully integrated into clinical medicine, providing surgeons with real-time visualization of important tissues and complex anatomy, where FGS imaging systems operate almost exclusively in the near-infrared (NIR, 650 to 900 nm). Notably, this spectral range permits the detection of two NIR imaging channels for spectrally distinct detection., Approach: Herein, we evaluated the utility of spectrally distinct NIR nerve- and tumor-specific fluorophores for two-color FGS to guide HNSCC surgery. Using a human HNSCC xenograft murine model, we demonstrated that facial nerves and tumors could be readily differentiated using these nerve- and tumor-specific NIR fluorophores., Results: The selected nerve-specific fluorophore showed no significant difference in nerve specificity and off-target tissue fluorescence in the presence of xenograft head and neck tumors. Co-administration of two NIR fluorophores demonstrated successful tissue-specific labeling of nerves and tumors in spectrally distinct NIR imaging channels., Conclusions: We demonstrate a comprehensive FGS tool for cancer resection and nerve sparing during HNSCC procedures for future clinical translation., (© 2024 The Authors.)

We have co-developed a first-in-kind model of fluorophore testing in freshly amputated human limbs. Ex vivo human tissue provides a unique opportunity for the testing of pre-clinical fluorescent agents, collection of imaging data, and histopathologic examination in human tissue prior to performing in vivo experiments. Existing pre-clinical fluorescent agent studies rely primarily on animal models, which do not directly predict fluorophore performance in humans and can result in wasted resources and time if an agent proves ineffective in early human trials. Because fluorophores have no desired therapeutic effect, their clinical utility is based solely on their safety and ability to highlight tissues of interest. Advancing to human trials even via the FDA's phase 0/microdose pathway still requires substantial resources, single-species pharmacokinetic testing, and toxicity testing. In a recently concluded study using amputated human lower limbs, we were able to test successfully a nerve-specific fluorophore in pre-clinical development. This study used systemic administration via vascular cannulization and a cardiac perfusion pump. We envision that this model may assist with early lead agent testing selection for fluorophores with various targets and mechanisms.

Nerve damage is a major complication of surgery, causing pain and loss of function. We have identified novel near-infrared nerve-specific fluorophores that provide excellent nerve contrast with the ability to identify buried nerve tissue.

Accidental nerve damage or transection of vital nerve structures remains an unfortunate reality that is often associated with surgery. Despite the existence of nerve-sparing techniques, the success of such procedures is not only complicated by anatomical variance across patients but is also highly dependent on a surgeon's first-hand experience that is acquired over numerous procedures through trial and error, often with highly variable success rates. Fluorescent small molecules, such as rhodamines and fluoresceins have proven incredibly useful for biological imaging in the life sciences, and they appeared to have potential in illuminating vital nerve structures during surgical procedures. In order to make use of the current clinically relevant imaging systems and to provide surgeons with fluorescent contrast largely free from the interference of hemoglobin and water, it was first necessary to spectrally tune known fluorescent scaffolds towards near infrared (NIR) wavelengths. To determine whether the well-documented Si-substitution strategy could be applied towards developing a NIR fluorophore that retained nerve-specific properties of candidate molecules, an in vivo comparison was made between two compounds previously shown to highlight nervous structures - TMR and Rhodamine B - and their Si-substituted derivatives.