Colonoscopy, Biomarkers, and Targeted Therapy in Colorectal Cancer.

This review highlights the most versatile diagnostic test of colonoscopy  for CRC. It remains the gold standard diagnostic tools for CRC, and to prevent CRC by screening and removing the polyp or premalignant lesions. This work also provides the most promising biomarkers, which highlights the application of the novel biomarkers in conjunction with clinical and pathologic features have allowed for more individualized approaches and targeted therapy  to patients with CRC.CRC is the third most common cancer diagnosed, and the second leading cause of cancer-related  deaths worldwide. With a population totaling 273,523,621 people, Indonesia has an estimated of 396,914 new cases of all cancers and 234,511 cancer-related deaths. Among those cancer cases, an estimated of 34,189 new CRC cases and 17,786 CRC deaths occurred in 2020.  Most of CRC cases were located in the rectum compared to those in the distal colon or proximal colon.  Clinical signs, symptoms and therapeutic approaches vary, depending on the stage and the location of CRC.  Those cancer locations are different in terms of their associated molecular alterations.Biomarker tests of tumor tissue from colonoscopy biopsy can help doctors to select a specific CRC treatment, and the tests can be used to determine prognostic value, predictive factors and the targeted therapy.  Targeted therapies are recommended for advanced or mCRC patients with KRAS/NRAS/BRAF mutated or wild-type tumors, HER2-amplified tumors, and NTRK gene fusion-positive, while immunotherapy is only offered for tumor with MSI-High (dMMR) status. The biomarkers and targeting approaches against colorectal CSCs are being developed and will be quite challenging.