Studies of the Cell Proliferating Ability of Flat Type Colorectal Cancer by using CD44 Immunostaining Method and Double Staining Method of Ki67-AgNORs

Author investigated the cell infiltrative activity, cell growth and cell proliferative activity of flat type colorectal cancer. Tissue specimens were obtained by surgery. These specimens were examined in expression of CD44 for the evaluation of cell infiltrative activity and Ki67 for growing cell, and then double-staining for AgNORs and Ki67 was performed to evaluate proliferative activity in growing cells. Analysis was performed by determining the labeling index (LI) of CD44 and Ki67, and the number of AgNORs in total 19 cases of type Is, type IIa, type IIa+IIc and type IIc. CD44 LI was 43% for type Is, 47% for type IIa, 55% for type IIa+IIc plus IIc, and a tendency of higher expression was presented in flat-elevated-with-depressed and flat-with-depressed tumors of type IIa+IIc plus IIc. Ki67 LI showed almost parallel data in three types. By double-staining method, the results of AgNORs counts in Ki67 negative cells were similar to those of Ki67 LI indicating that the proliferative activity was not different between tumors. In contrast, AgNORs counts in Ki67 positive cells were 8.48 in type Is, 7.67 in type IIa, and 10.75 in type IIa+IIc plus IIc, and the highest proliferative activity was presented in flat-elevated-with-depressed and flat-with-depressed tumors of type IIa +IIc plus IIc. (p<0.05) Author's results suggest that the flat-elevated-with-depressed and flat-with-depressed tumor have a different characteristics compared with two types and is higher malignant and potentially invasive colorectal cancers than the other types.