Study of Ras Oncogene Products Expression in Colorectal Cancer

Abstract

We studied immunohistochemically ras oncogene products (ras p 21) expression in 120 colorectal cancers. Positive staining of ras p 21 was detected in 63 (52.5 %) of 120 colorectal cancers. Positive staining of ras p 21 was more frequently detected in advanced stage, namely the incidence of positive staining for ras p 21 was significantly higher in cases with invasion of depth of ss (a₁) or beyond ss (a₁), lymphatic vessel invasion and lymph node metastasis.
There was no relationship between the incidence of ras p21 expression and DNA ploidy pattern or DNA index.
The prognosis of colorectal cancers showing negative ras p 21 was significantly better than that of cancers showing positive ras p 21 (p<0.05). PCNA labeling index and Ag-NORs dot number in ras p 21 positive area of cancer tissues were significantly higher than those in ras p 21 negative area.
Therefore we supposed that the proliferative activity in ras p 21 positive carcinoma was higher than in ras p 21 negative one.
These results suggested that ras oncogene expression related to the progression and to the prognosis of colorectal cancer.