Prognostic impact of the combination of p16, p21 and Immunoscore in rectal cancer.

BACKGROUND

The association between p16 and p21, a marker of cellular senescence, and the Immunoscore, an immunological prognostic indicator, in rectal cancer patients undergoing curative surgery were investigated.

METHODS

A total of 82 patients who underwent curative surgery for rectal cancer were evaluated. The resected specimens were analyzed for p16, p21, CD3 and CD8 expression by immunohistochemistry. Immunoscore was calculated on the basis of CD3 and CD8 expressions. The clinicopathological characteristics and long-term outcomes were evaluated.

RESULTS

Among the 82 patients, 24 (29.3%) were p16-positive and 11 (13.4%) were p21-positive. The patients were classified into the following five Immunoscore groups (IS0-5). IS0, IS1 and IS2 were classified as the low Immunoscore group (45 patients, 54.9%) and IS3 and IS4 as the high Immunoscore group (37 patients, 45.1%). There was no significant difference in age, sex, body mass index, American Society of Anesthesiologists physical status, depth of invasion of the tumor, lymph node metastasis and histological classification of the tumor with p16 or p21 expression or Immunoscore. p16-positive expression and low Immunoscore each showed a tendency to indicate poor prognosis of disease-free survival (DFS). Patients with the combination of p16 and p21 positivity and with p16 positivity and low Immunoscore showed significantly poor prognosis of DFS. Patients with p21 positive positivity and low Immunoscore tended to have worse DFS.

CONCLUSIONS

p16, p21 and Immunoscore may be prognostic indicators of rectal cancer. The combination of them may provide more accurate prognostic prediction than either factor alone.