CIMP Status in Colorectal Cancer in Uganda: A Cross-Sectional Study

Wismayer R, Matthews R, Whalley C, Kiwanuka J, Kakembo FE, Thorn S, Wabinga H, Odida M and Tomlinson I

Published on: 2025-01-18

Abstract

Introduction: A recognized subgroup of colorectal cancer (CRC) known as CpG island methylator phenotype (CIMP) is associated with particular patient outcomes and genetic defects in developed high-income countries. However, in Uganda the CIMP status of colorectal cancer has not been determined despite the increase in the incidence of CRC according to the Kampala Cancer Registry. Hence the objective of this cross-sectional study was to determine the CIMP status of colorectal cancer in Ugandan patients.

Methodology: We analyzed CIMP status in 92 CRC patients using a 14-gene panel which included APC, CACNA1G (MINT31), CDKN2A, CRABP1, IGF2, IGFBP3, MGMT, RASSF1, SEPTIN9, SFRP2, SOCS1, SV2C(MINT 1), TMEFF1(HPP1), and WIFI. CIMP was defined when more than ≥6 genes out of the 13 gene panel were methylated. One of the genes, IGFBP3 failed an assay in all the samples and therefore thirteen (13) genes in the panel were used.

Results: Out of 92 cases which had an adequate quantity of DNA to carry out CIMP analysis, 11(11.9%) were CIMP positive and 81(88.0%) were CIMP negative. CIMP positive tumours represented 3(5.8%) of MSI positive tumours compared with 8(10.7%) of MSS tumours.

Conclusions: Compared to Western developed high-income countries, in Uganda the prevalence of CIMP positive tumours is low. CIMP is a distinct epigenetic subtype of colorectal cancer in Ugandan patients.