Since, it is well acknowledged that colorectal tumors exhibit increased levels of different markers of oxidative stress compared to non-tumoral tissues [42], it can be surmised that the level of mtROS might be significantly increased in all CMS subtypes, compared to NT samples and might be the highest in CMS4 among tumors, due to an inversely correlated CI enzyme activity. Here, NDUFB6 is linked to colorectal neoplasm.