Primary Tumor Histology is a Potential Independent Predictor of Oncological outcomes in Colorectal Cancer

Abstract Introduction/Objective Evaluation of the primary tumor histology can identify features in the tumor microenvironment (TME) that are intricately linked to molecular changes and aggressive tumor behavior in colorectal cancer (CRC). In this study, we evaluated the primary tumor histology such as the tumor histologic subtype, the presence of poorly differentiated clusters (PDCs), and stromal desmoplastic reaction (SDR), and determined their relationship with tumor grade, stage, and DNA mismatch repair (DNA MMR) gene status. Methods/Case Report This was a retrospective study. Hematoxylin and eosin-stained microarray sections of CRC tissues in 208 patients were pathologically evaluated. PDC was defined as a cluster of ≥ 5 nuclei in the stroma with no glandular differentiation. SDR was defined as stromal connective tissue remodeling. Parallel sections were stained with antibodies against the MLH1, PMS2, HMS6, and HMS2 for their expression. Statistical analysis was performed for the association between the variables Results (if a Case Study enter NA) There were 208 patient samples, 113 were males (54.3%) and 95 were females (45.7%). 61.5% were ≥ 50 years and 38.5% were less than 50 years. 59.4% and 37.5% of stages II and III tumors had PDCs. Univariate analysis showed a strong association between tumor grade, stage, and SDR (p=0.005 and p= 0.013 respectively) but not with PDC and MMR deficiency. 16.8% of tumors had MMR deficiency which was more prevalent in adenocarcinoma with mucinous components (27%). Multivariate analysis showed a strong association with PDC and tumor stage (p=0.026), tumor subtype and stage and grade (p=0.007, p= 0,023), stage, and SDR (p = 0.026). Grade, stage, SDR, and MMR all showed very strong association (p=0.005, p=0.019). Conclusion Our data shows that tumor histology is an independent predictor of oncological outcomes in CRC. Future longitudinal studies on prospective cohorts are required to validate our observations and increase the power of our deductions.