MLH1 and Fanconi anemia: Notably, the MCPyV-negative tumors expressed significantly reduced levels of DNA damage response genes, such as MSH2 and MLH1, and Fanconi anemia family genes, FANCA and FANCC, suggestive of a potential mechanism for the accumulation of the large amount of somatic mutations identified in the MCPyV-negative genome and the low number of somatic mutations in the MCPyV-positive tumors (see Table S2).