Breast cancer (BC) is the most common form of cancer among women in developing countries, accounting for about 18% of all female cancers although mortality rates are declining in some countries, it remains the leading cause of death among women aged 35-55 years (Michael B and Harvey S, 2000). In Iraq, cancer of the breast is the commonest cancer in females, in 2005 constituted 31% of all other malignancies in women (Iraqi National Cancer Registry 2005). Proliferative markers had been used to study proliferation rates in malignant tissues have a strong prognostic value for several types of cancer, including breast cancer. Ki-67, MIB-1 and proliferative cell nuclear antigen as proliferative markers had been studied in various tumors such as colorectal carcinoma, Ewing's sarcoma, gastric carcinoma and breast carcinoma.Aim of the study
to assess the immunohistochemical expression of Ki-67 and PCNA as proliferative markers in breast cancer (Invasive ductal and Invasive lobular carcinomas), in correlation with some clinicopathological parameters (age of patient, tumor size, menopausal status, tumor grade and lymph node status). Patients, materials and methods From March 2008 to July 2008, total of (45) tissue samples of surgical breast biopsies (33 mastectomy case and 12 cases of excisional biopsies) were included in this retrospective study. Forty one cases were of invasive ductal carcinomas and (4) cases of invasive lobular carcinomas. The samples were obtained from archival paraffin embedded blocks for the years (2006) to (2008) from the histopathology files of department of pathology of Al-kadhimiya Teaching Hospital, Teaching Laboratories of medical city Hospital and Dr.Raji Al-Hadithi private Laboratory. The histopathological diagnosis had been revised and all cases were stained by immunohistochemical technique with Ki-67 and PCNA tumor markers. Results From the clinicopathological assessment, the size of tumor (the largest diameter) was found to be significantly related to the axillary lymph node metastasis (P-value = 0.0241). Regarding Immunohistochemical expression of Ki-67, fourteen invasive ductal carcinoma cases out of 41(34.1%) and one invasive lobular carcinoma case out of 4(25%) were Ki-67 with high expression, and there was a significant difference regarding Ki-67 expression in relation to different age groups of the patients, in premenopausal women the mean value of the total Ki-67 labeling index was higher than that of postmenopausal women, however the difference was non significant P > 0.05. Regarding the grade of the tumor in invasive breast carcinomas there was a significant difference between Ki-67 expression and the three grades of the tumor with a P-value 0.0473. Cases with lymph node involvement showed a significant positive immunohistochemical expression of Ki-67, so as for tumor size in which tumors of (>5cm) showed a significant Ki-67 expression in comparison to tumors of size (2.1-5cm) and (0-2cm). Regarding PCNA immunohistochemical expression Fifteen invasive ductal carcinoma cases out of 41(36.5%) and two invasive lobular carcinoma case out of 4(50%) showed a high expression of PCNA. There was no significant difference in PCNA expression between different age groups of the patients and so as regarding the menopausal states. PCNA immunohistochemical expression was significantly different in different grades of invasive breast carcinomas. The mean value of PCNA labeling index showed no significant difference between cases with positive lymph node involvement and those with a negative lymph node involvement, also there was no significant correlation in PCNA immunohistochemical expression in relation to the tumor size. There was a weak positive correlation between Ki-67 expression and PCNA expression in invasive breast carcinoma (r = 0.227) and this correlation was not significant (P-value = 0.364). Conclusions •A significant correlation has been found between Ki-67 immunohistochemical expression and the clinicopathological variables (age of patients, grade of tumor, lymph node status and tumor size), and no significant correlation with menopausal status, in cases of invasive breast carcinoma. •There was a significant correlation between PCNA immunohistochemical expression and grade of tumor in cases of invasive breast carcinomas, however no significant correlation had been found between PCNA immunohistochemical expression and other clinicopathological variables (age of patients, menopausal status, tumor size and lymph node status).
• No significant correlation between the PCNA and Ki67 immunohistochemical expression in invasive breast carcinoma had been identified.