Different histopathological methods have been developed to estimate tumor response to pre-operative therapies, including distinction between presence or absence of viable cancer cells (using H&E or, in case of doubts, immunostaining of CK20 and CK7 for a better visualization of colorectal tumor cells and dystrophic biliary structures, respectively) [36]; assessment of the percentage of viable tumor in relation to the total tumor area [35,37] and the evaluation of tumor thickness at the tumor-normal interface [38]. The gene discussed is KRT7; the disease is neoplasm.