Complex sentence: MSI tumors in 15% of sporadic colorectal cancer result from the hypermethylation of the MLH 1 gene promoter, whereas MSI tumors in Lynch syndrome are caused by germline mutations in MLH 1, MSH 2, MSH 6, and PMS2.
Split into simpler sentences: MSI tumors in 15% of sporadic colorectal cancer result from the hypermethylation of the MLH 1 gene promoter. Whereas, MSI tumors in Lynch Syndrome are caused by germline mutations in MLH 1, MSH 2, MSH 6 and PMS2.