Clinical and immunopathological evaluation and its comparison with IHC consensus molecular subtypes of colorectal cancer

Abstract

Abstract This study examined the prognostic significance of immunoscore within consensus molecular subtypes (CMS), tumour budding (TB), and macrophage infiltration in colorectal cancer (CRC). A retrospective series was analysed using immunohistochemical staining, immunoscore evaluation, and CMS classification, according to established methods. Among the 255 patients with CRC, 34.9% had stage III disease. The CMS classification showed a predominance of CMS2/3 (69.4%), with relapse occurring across all the subtypes. Low immunoscore was frequent in conventional and serrated adenocarcinomas, as well as in CMS2/3, whereas MSI-H correlated with intermediate-high immunoscore. TB was prevalent in relapsed patients, particularly in CMS2/3 and CMS4, and was linked to serrated histology. TB of ≥ 20 foci was correlated with hepatic metastases. CD163+ macrophage infiltration was common in CMS1 and CMS2/3, and was associated with high immune scores. TB influenced overall and relapse-free survival, whereas CMS affected the overall survival. Immunoscore were not associated with survival. The associations identified between CMS subtypes and clinical as well as pathological characteristics enhance the understanding of CMS behaviour in clinical practice.