Abstract 3419: Demographic, health history, and lifestyle factors in association with biomarkers of colorectal cancer prognosis: A pilot study

Abstract

Abstract Background/Objectives: Multiple demographic, health history, and lifestyle factors have been associated with prognosis of colorectal cancer (CRC), but the mechanisms underlying these associations remain poorly understood. Knowledge of these mechanisms could reveal new strategies to improve outcomes among CRC patients. The primary objective of this project was to explore the association of these factors, which were assessed pre-diagnostically, with expression of two biomarkers in CRC tumors, SPARC and PD-L1, for which lower and higher levels of expression, respectively, have been previously associated with poorer CRC prognosis. Methods: Participants were drawn from the British Columbia Generations Project (BCGP). At the time of recruitment, they completed a detailed questionnaire that ascertained demographic factors (e.g., biological sex and household income), health history (e.g., personal history of CRC screening), and lifestyle factors (daily fruit and vegetable consumption and alcohol consumption). Formalin-fixed paraffin-embedded blocks (FFPE) with adequate volumes of tumor were obtained for 49 incident CRC cases diagnosed within the BCGP. Cores were extracted from the blocks to create tumor tissue microarrays (TMAs). Slides created from thin sections of the TMAs were stained with SPARC and PD-L1 antibodies and then imaged and analyzed to calculate H-scores as measures of expression in both epithelial and non-epithelial tissues. Linear regression analyses were conducted to evaluate associations between the various factors and ln-transformed H-scores. Results: Compared to non-smokers, smokers, on average, had 47% lower SPARC H-scores (p=0.05) in the epithelial tissues of their CRC tumors. Individuals with incomes higher than $74,999/year had 33% higher SPARC H-scores (p=0.04) in their CRC tumor non-epithelial tissues than those who earned less than $74 999/year. Females had 2.8-fold greater PD-L1 H-scores (p=0.005) in their CRC tumor epithelial tissues than males. Compared to those without a history of CRC screening, those with a history of CRC screening had 2.2 and 2.0-fold greater PD-L1 H-scores in their epithelial and non-epithelial CRC tumor tissues, respectively. Conclusion: Larger-scale studies with prognostic data are needed to confirm our findings, but our results suggest that differences in the expression of SPARC and PDL-1 may contribute to the previously observed impacts of some demographic, healthy history, and lifestyle factors on CRC prognosis. Citation Format: Umaimah Zanif, Isabella Tai, Stephen Yip, Sindy Babinszky, Katy Milne, Peter Watson, Rachel Murphy, Parveen Bhatti. Demographic, health history, and lifestyle factors in association with biomarkers of colorectal cancer prognosis: A pilot study [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 3419.