Ascending and transverse colon tumors were associated with concentrations of maspin in tumoral tissue higher than 295 pg/mL (7 of 9 patients—77.77%), while tumors found in the descending colon, sigmoid colon, rectosigmoid colon, and rectal tumors were associated with values of the maspin concentration in tumoral tissue lower than 295 pg/mL (18 of 21 patients—85.71%). The gene discussed is SERPINB5; the disease is rectal neoplasm.