The presence of eosinophils in the lamina propria, particularly on the acute and early regenerative

phase was noted in almost all specimens. However, in contrast with the radiation colitis induced by pre-operative irradiation no “”eosinophil crypt Protein Tyrosine Kinase inhibitor abscesses”" was observed, even in acute injury. Figure 2 Histopathological findings of radiation-induced colitis. A. Acute injury, characterized by ulceration, absence of viable crypts, diffuse infiltration by polymorphonuclear leucocytes, and prominent capillaries lined by plump endothelial cells (H + E × 400). B. Early regenerative check details changes, characterized by absence of ulceration, considerably less acute inflammation, infiltration by plasma cells and lymphocytes, presence of viable crypts with disarray, absence of cryptitis or acute epithelial damage (H+E × 400). C.

Late regenerative changes, characterized by absence of acute inflammation, mild diffuse infiltration by plama cells and lymphocytes, architectural crypt distortion, with reduced crypts, crypt branching and shortening as well as moderate/severe fibrosis of the lamina propria (H + E × 400). Figure 3 Immunohistochemical expression of active caspase 3 in apoptotic epithelial cells. In a minority of our patients an acute mucosal injury, was diagnosed histologically. More specifically, of all patients administered amifostine, none exhibited acute mucosal injury, regardless of the biopsy timing (early or late). Furthermore,

of the eight patients receiving amifostine and Afatinib undergoing early biopsies, four (50%) exhibited early regenerative changes; two (25%) late regenerative changes and two (25%) had no abnormal histological findings. Of the fourteen patients receiving amifostine and undergoing late biopsies, three (21.4%) showed early regenerative changes, nine (64.3%) late regenerative changes and two (14.3%) had no abnormal histological findings. Acute mucosal injury was histologically characterized in three patients who did not receive amifostine; in two out of the seven (28.6%) patients with early biopsies and one out of the fifteen patients with late biopsies (6.7%). Furthermore, in arm R, early biopsies early regenerative changes in two (28.6%) and late regenerative changes in two (28.6%) patients. In the same group, late biopsies revealed early regenerative changes in five (33.3%) and late regenerative changes in eight (53.3%) patients.