Cancer disparities in low- and middle-income countries (LMICs) arise from multifaceted interactions between environmental exposures, infectious agents, and systemic inequities, such as limited access to care. The exposome, a framework encompassing the totality of non-genetic exposures throughout life, offers a powerful lens for understanding these disparities. In LMICs, populations are disproportionately affected by air and water pollution, occupational hazards, and oncogenic infections, including human papillomavirus (HPV), hepatitis B virus (HBV), Helicobacter pylori (H. pylori), human immunodeficiency virus (HIV), and neglected tropical diseases, such as schistosomiasis. These infectious agents contribute to increased cancer susceptibility and poor outcomes, particularly in immunocompromised individuals. Moreover, climate change, food insecurity, and barriers to healthcare access exacerbate these risks. This review adopts a population-level exposome approach to explore how environmental and infectious exposures intersect with genetic, epigenetic, and immune mechanisms to influence cancer incidence and progression in LMICs. We highlight the critical pathways linking chronic exposure and inflammation to tumor development and evaluate strategies such as HPV and HBV vaccination, antiretroviral therapy, and environmental regulation. Special attention is given to tools such as exposome-wide association studies (ExWASs), which offer promise for exposure surveillance, early detection, and public health policy. By integrating exposomic insights into national health systems, especially in regions such as sub-Saharan Africa (SSA) and South Asia, LMICs can advance equitable cancer prevention and control strategies. A holistic, exposome-informed strategy is essential for reducing global cancer disparities and improving outcomes in vulnerable populations.

Colonoscopy remains the gold standard for colorectal cancer (CRC) screening, but its invasiveness, cost, and limited availability in resource-constrained settings pose major barriers. Stool-based methylated DNA biomarkers, such as vimentin, offer sensitive, non-invasive alternatives. Given the high burden of HIV and helminth co-infections in sub-Saharan Africa and their potential contribution to cancer susceptibility, this study investigated whether stool-derived vimentin methylation could detect early oncogenic changes in these high-risk groups. In this retrospective cross-sectional study, archived stool samples from 62 South African adults were stratified into five groups: uninfected controls, HIV-infected only, helminth-infected only, HIV-helminth co-infected, and CRC-confirmed patients. DNA was extracted, bisulfite-converted, and analyzed for vimentin methylation using a high-resolution melt assay. Fecal occult blood testing (FOBT) was also performed. Vimentin methylation differed significantly across groups (p < 0.0001). CRC cases showed 90% methylation, confirming its role as a CRC biomarker. Interestingly, vimentin methylation frequencies were also observed in HIV-only (92.9%, p < 0.0001 vs. controls), helminth-only (93.3%, p < 0.0001), and HIV-helminth co-infected (77.9%, p < 0.0001) individuals without diagnosed cancer, compared to 10% in controls. Methylation levels in infected groups were not significantly different from CRC patients (all p > 0.05), suggesting infection-induced epigenetic changes of comparable magnitude to malignancy. To support these results, DNMT1–RG108 molecular docking (PDB 4WXX, Maestro 2025-3) demonstrated stable binding (GlideScore −6.285 kcal/mol; ΔG_bind −49.61 kcal/mol) via hydrogen bonding with Glu1266 and Asn1578 and π–π stacking with Phe1145, providing a mechanistic explanation for infection-driven vimentin methylation. No significant differences were found between infected groups. FOBT was positive in 83.3% of CRC cases, with only sporadic positives in infected groups. These findings provide novel evidence that chronic HIV and helminth infections are associated with vimentin promoter methylation at levels indistinguishable from CRC. This supports the hypothesis that persistent infection-driven inflammation promotes early epigenetic reprogramming toward oncogenesis. In high-burden African settings, stool-based methylation assays could serve as early diagnostic tools to identify at-risk individuals long before clinical disease manifests, enabling targeted surveillance and prevention.

Tumor mutational burden (TMB) and tumor-infiltrating lymphocytes (TILs) are key biomarkers for predicting immunotherapy responses in cutaneous melanoma. The discordance between brisk TIL morphology and absent cytokine signals complicates immune profiling. We examined the interactions between TMB, TIL patterns, cytokine expression, and genomic alterations to uncover immune escape mechanisms and refine prognostic tools. A structure-based BRAF druggability analysis was performed to anchor the genomic findings in a therapeutic context. Primary cutaneous melanoma cases (N = 205) were classified as brisk (n = 65), non-brisk (n = 60), or absent TILs (n = 80) according to the American association for cancer research (AACR) guidelines. Inter-observer concordance was measured using intraclass correlation. Tumor necrosis factor alpha (TNF-α) and interferon gamma (IFN-γ) levels were graded using immunohistochemistry. Eleven brisk TIL cases lacking TNF-α expression were analyzed using the (Illumina TruSight Oncology 500, Illumina-San Diego, CA, USA). Dabrafenib docking to the BRAF ATP site was performed with Glide SP/XP and rescored with Prime MM-GBSA. Brisk TILs lacking cytokine signals suggested post-translational silencing of TNF-α/IFN-γ. Among the 11 profiled cases, eight exhibited high TMB and copy number alterations, with enrichment of nine metastasis/immune regulation genes. Inter-observer concordance was high (absent TILs, 95%; brisk TILs, 90.7%). BRAF docking yielded a canonical type-I pose and strong ATP pocket engagement (ΔG_bind −84.93 kcal·mol⁻¹). Single biomarkers are insufficient for diagnosis. A multiparametric framework combining histology, cytokine immunohistochemistry (IHC), and genomic profiling enhances stratification and reveals immune escape pathways, with BRAF modeling providing a mechanistic anchor for the targeted therapy.