Immunohistochemical evaluation of Ki-67, PCNA and MCM2 proteins proliferation index (PI) in advanced gastric cancer

The current study objective was to assess the proliferation indices (PI) of Ki-67, PCNA and MCM2 proteins in advanced gastric cancer and in metastatic lymph node in correlation with certain clinicopathological features and with postoperative survival of patients. The study was conducted in a group of 100 patients with advanced gastric cancers. Involvement of local lymph nodes was present in 36 cases. Immunohistochemical investigations were carried out using monoclonal antibodies against Ki-67 (DAKO), PCNA (DAKO) and polyclonal antibody to MCM2 (Santa Cruz Biotechnology). Visualization of the antigen/antibody complex was performed using LSAB technique (biotin-streptavidin-peroxidase) followed by application of chromogene DAB (DAKO). Statistical analysis revealed no correlations of Ki-67, PCNA and MCM2 PI in tumour tissue or metastatic lymph node with patients' age and gender, tumour location, histological grade, macroscopic type according to Bormann's classification and histological grading by Lauren's and Goseki's classifications. Moreover, no correlation was observed of Ki-67 and MCM2 PI in tumour tissue with histological grading. No correlation was also noted between the proliferation indices of all the three proteins in the affected lymph node and grade of histological differentiation. Such clinicopathological parameters as patients' age and gender, histological grading by Lauren's and Goseki's classifications and lymph node involvement did not correlate with survival time of patients. Furthermore, no statistically significant correlation was shown of postoperative survival time with Ki-67 and MCM2 PI in tumour tissue and metastatic lymph nodes and with PCNA PI in the affected lymph nodes. However, a statistically significant correlation was found of Ki-67, PCNA and MCM2 PI in tumour tissue and metastatic lymph nodes with depth of wall invasion and local lymph node involvement. A statistically significant correlation was also noted between PCNA PI in the main mass of tumour and histological grading. The postoperative survival time of patients exhibited a statistically significant correlation with tumour location and macroscopic type according to Bormann's classification. Correlations on statistical borderline were noted between survival time and depth of gastric wall invasion and PCNA PI in the main mass of tumour.