These algorithms evaluated the degree of importance of the studied variables in the response to preoperative RTC treatment, showing that, both the presence of tumor involvement in ≥4 perirectal lymph nodes (N2) and the 4q loss were the most influential variables in the response to treatment with preoperative RCT, followed by the presence of tumor involvement in 1 to 3 perirectal lymph node (N1), the abnormalities of the 15q11.1, 17q21.31, and 15q14 chromosomal regions, and CEA serum levels (Figure 2 and Table 4). This evidence concerns the gene CEACAM5 and neoplasm.