Colorectal cancer (CRC) is one of the most common cancer types in both men and women worldwide, with 1.2 million new cases annually. CRC is broadly classified into three molecular phenotypes: microsatellite instable, MSI (15%), chromosome instable (CIN), and CpG-island methylator phenotype (CIMP). Patients with MSI have better prognosis than those with microsatellite stable (MSS) tumours (85%), but there is substantial heterogeneity in risk within the groups. There is room for better tools for risk stratification to support individualized treatment.
The present invention is a novel clinical biomarker for CRC based on measurement of intracellular expression of the RCC2 protein in a biopsy or tissue piece from CRC, which will provide prognostic information for clinically important patient subgroups. Intracellular staining of RCC2 provides prognostic information (overall survival, time to regression) for female but not male patients. Prognostic value is associated with MSS but not MSI subset.
Furthermore, among female MSS patients, RCC2 identifies high risk patients in the stage II and rectal cancer patient subgroups, where the clinical need is particularly pronounced, due to a heterogenous risk profile. Stage II and rectal cancer patients identified as having poor prognosis/ high risk should be offered adjuvant chemotherapy after surgery not generally offered to these groups of patients based on current clinical criteria.
An international patent application protecting the invention has been filed.