A COMPARATIVE-STUDY OF NUCLEOLAR ORGANIZER REGION, PROLIFERATING CELLNUCLEAR ANTIGEN AND EPIDERMAL GROWTH-FACTOR RECEPTOR STAINING IN COLON TUMORS

Several studies have reported that proliferating cell nuclear antigen (PCNA), nucleolar organizer regions (NOR) and epidermal growth factor receptor (EGF-R) are cellular proliferation parameters in malignant ru mours. However, the correlation of EGF-R with PCNA and NOR has not bee n reported in colon rumours. To clarify this, we investigated the corr elation of the expression of EGF-R with PCNA and NOR in colonic epithe lial rumours. Using immunohistochemical staining and one-step silver s taining techniques, the expressions of EGF-R-, PCNA- and NOR-associate d protein were studied in paraffin sections from five normal mucosae, 10 adenomas with mild atypia, 16 adenomas with moderate atypia, 32 ade nomas with severe atypia including carcinoma in situ and 47 with invas ive colon carcinomas. Significant differences were found among the res pective degrees of atypia in Ag-NOR counts, PCNA labelling index (LI), and the expression of EGF-R. However, there were no significant diffe rences among the Ag-NOR counts of the severe atypia and invasive carci noma. There was a significant positive correlation between Ag-NOR coun ts and PCNA LI (P < 0.001). The Ag-NOR counts and PCNA LI in EGF-R-pos itive cases were higher than in EGF-R-negative cases (P < 0.001). Thes e results indicate that each of the parameters increased significantly with the increase in atypia and the progression of cancer. Epidermal growth factor receptor provokes an exacerbation of protein synthesis a nd the cell cycle in colonic epithelial tumours.