Ethnicity-Specific Molecular Alterations in MAPK and JAK/STAT Pathways in Early-Onset Colorectal Cancer.

Background/Objectives: Early-onset colorectal cancer (EOCRC), defined as colorectal cancer (CRC) diagnosed before the age of 50, has been increasing in incidence, particularly among Hispanic/Latino (H/L) populations. Despite this trend, the underlying molecular mechanisms driving EOCRC disparities remain poorly understood. The MAPK and JAK/STAT pathways play critical roles in tumor progression, proliferation, and treatment response; however, their involvement in ethnicity-specific differences in EOCRC remains unclear. This study aims to characterize molecular alterations in MAPK and JAK/STAT pathway genes among EOCRC patients, focusing on differences between H/L and Non-Hispanic White (NHW) patients. Additionally, we assess whether these pathway-specific alterations contribute to survival outcomes in H/L EOCRC patients. Methods: We conducted a bioinformatics analysis using publicly available CRC datasets to assess mutation frequencies in MAPK and JAK/STAT pathway genes. A total of 3,412 patients were included in the study, comprising 302 H/L patients and 3,110 NHW patients. Patients were stratified by age (EOCRC: <50 years, late-onset colorectal cancer -LOCRC: ≥50 years) and ethnicity (H/L vs. NHW) to evaluate differences in mutation prevalence. Chi-squared tests were performed to compare mutation rates between groups, and Kaplan-Meier survival analysis was used to assess overall survival differences based on pathway alterations among both H/L and NHW EOCRC patients. Results: Significant differences were observed in MAPK pathway-related genes when comparing EOCRC and LOCRC in H/L patients. NF1 (11.6% vs. 3.7%, p = 0.01), ACVR1 (2.9% vs. 0%, p = 0.04), and MAP2K1 (3.6% vs. 0%, p = 0.01) were more prevalent in EOCRC, while BRAF mutations (18.3% vs. 5.1%, p = 9.1e-4) were significantly more frequent in LOCRC among H/L patients. Additionally, when comparing EOCRC in H/L patients to EOCRC in NHW patients, key MAPK pathway genes such as AKT1 (5.1% vs. 1.8%, p = 0.03), MAPK3 (3.6% vs. 0.7%, p = 6.83e-3), NF1 (11.6% vs. 6.1%, p = 0.02), and PDGFRB (5.8% vs. 2.1%, p = 0.02) were significantly enriched in H/L EOCRC patients. However, no significant differences were observed in JAK/STAT pathway-related genes when comparing EOCRC and LOCRC in H/L patients, nor when comparing EOCRC in H/L vs. NHW patients. Survival analysis revealed borderline significant differences in H/L EOCRC patients, whereas NHW EOCRC patients with no alterations in the JAK/STAT pathway exhibited significant survival differences. In contrast, MAPK pathway alterations were not associated with significant survival differences. These findings suggest that MAPK and JAK/STAT pathway disruptions may have distinct prognostic implications in H/L EOCRC patients, justifying further investigation into their potential role in cancer progression and treatment response. Conclusions: These findings suggest that MAPK pathway dysregulation plays a distinct role in EOCRC among H/L patients, potentially contributing to disparities in CRC development and treatment response. The higher prevalence of MAPK alterations in H/L EOCRC patients compared to NHW patients underscores the need to explore ethnic-specific tumor biology and therapeutic targets. Conversely, the lack of significant differences in JAK/STAT pathway alterations suggests that this pathway may not play a major differential role in EOCRC vs. LOCRC within this population. Survival analysis highlighted the prognostic relevance of pathway-specific disruptions. These insights emphasize the importance of precision medicine approaches that consider genetic heterogeneity and pathway-specific alterations to improve outcomes for H/L CRC patients.