The Clinical Significance of Cathepsin D and p53 Expressionin Locally Advanced Rectal Cancer

Kim, Jun Sang; Lee, Shengjin; Kim, Jin Man; Cho, Moon June

Abstract

PURPOSE: Cathepsin D (CD) is a lysosomal acid proteinase that is related to malignant progression, invasion, and a poor prognosis in several tumors. The aim of this study was to evaluate the prognostic clinical significance of CD and p53 expression in pretreatment biopsy specimens from patients with locally advanced rectal cancer who were treated with preoperative chemoradiation. MATERIALS AND METHODS: Eighty-nine patients with locally advanced rectal cancer (cT3/T4 or N+) were included in this study. Preoperative chemoradiation consisted of a dose of 50.4 Gy of pelvic radiation and two concurrent cycles of administration of 5-fluorouracil and leucovorin. Surgery was performed six weeks after chemoradiation. CD and p53 expression in pretreatment formalin-fixed paraffin-embedded tumor biopsy specimens were assessed by immunohistochemical staining using a CD and p53 monoclonal antibodies. The threshold value for a positive stain in tumor tissue and stromal cells was 1+ intensity in 10% of the tumors or stromal cells, respectively. RESULTS: Positive CD expression was found in 57 (64%) of the tumors and 32 (35%) of the stromal cell specimens. There was no association with CD expression of the tumor or stromal cells and patient characteristics. There was a correlation between tumor CD expression with stromal cell CD expression (p=0.01). Overexpression of p53 was not a significant prognostic factor. The 5-year overall survival (OS) and disease-free survival (DFS) rates were not different between tumor CD-negative and positive patient biopsy samples (69% vs. 65%, 60% vs. 61%, respectively). The 5-year OS rates in the tumor-negative/stromal cell-negative, tumor-negative/stromal cell-positive, tumor-positive/stromal cell-negative and tumor-positive/ stromal cell-positive biopsy samples were 75%, 28%, 62%, and 73%, respectively. Stromal cell staining only without positive tumor staining demonstrated the worst overall survival prognosis for patients (p=0.013). CONCLUSION: Overexpression of p53 in rectal biopy tissue was not associated with prognostic significance. In the pretreatment biopsy specimens, an exclusive increase in CD expression in stromal cells without tumor expression was related to poor overall survival in patients with locally advanced rectal cancer treated with preoperative chemoradiation.