The present study aims to determine the prevalence of dMMR in selected solid tumors (CRC and the more common non-CRC cohort [gastric, esophageal, and endometrial cancer]) in the study population in terms of percentage and/or frequency by tumor type and patient characteristic (age, gender, initial tumor/metastasis) and to describe the biomarker profile of colorectal cancer patients (dMMR, KRAS, NRAS, BRAF). Here, KRAS is linked to colorectal cancer.