Background: Proliferating cell nuclear antigen (PCNA), a proliferation marker, epidermal growth factor receptor (EGFR), a glycoprotein that plays a role in tumorigenesis by binding the mitogenic epidermal growth factor, and P-glycoprotein, the mdr gene product, are considered to be of prognostic relevance in different tumor types. Parameters that allow prediction of the course of disease in colorectal cancer would aid the development of improved treatment strategies.
Methods: Immunohistochemical staining was performed on paraffin-embedded sections of 82 colorectal adenocarcinomas and 18 lymph node metastases. EGFR and P glycoprotein expression was evaluated semiquantitatively; PCNA expression was analyzed quantitatively.
Results: An inverse relationship between the percentage of PCNA-positive cells and survival times could be demonstrated, survival differed significantly among the quartiles (P < 0.02). The median and range of the percentage of PCNA-positive cells in primary tumors and lymph node metastases were similar. The extent of EGFR expression also revealed significant differences concerning survival times; patients with more than 50% stained tumor cells had a poorer prognosis than those with less than 50% stained cells. P-glycoprotein expression was found to have no influence on survival.
Conclusions: Knowledge of the percentage of PCNA-positive cells could be especially helpful in deciding whether to treat patients with localized disease further because adjuvant chemotherapy affects mainly dividing cells and should, therefore, be more successful in tumors with high proliferative activity.