Estrogen, Progesterone Receptors and Proliferating Activity Evaluated by Immunocytochemistry in Breast Cancer

Ki-67 expression in primary breast carcinomas and their axillary lymph node metastases: clinical implications

Proliferative activity of tumour cells assessed by immunohistochemical Ki-67 expression is one of several prognostic indicators in breast cancer. The major objective of this study was to investigate the prognostic impact of Ki-67 proliferative activity in the axillary lymph node metastases and in the matched primary breast carcinoma from 194 patients. There was a statistically significant up-regulation of Ki-67 protein in the metastatic deposit compared to where the primary tumour was found (p = 0.001). A low Ki-67 index in both the primary and the metastatic tumours was a favorable prognostic factor. A high index in both primary and metastatic lesion and an up-regulation from a low index in the primary tumour to a high index in the metastatic deposit represented an unfavorable prognostic factor. Multivariate analysis showed that Ki-67 expression in the metastases was a superior independent prognostic factor of clinical outcomes compared to that in the primary tumours. Ki-67 expression in > or =10% of carcinoma cells in the primary tumours and > or =15% in the nodal metastases seems to be optimal cut-off levels. Ki-67 is of value as an independent prognostic factor in breast cancer.

Ki-67 expression in breast carcinoma: its association with grading systems, clinical parameters, and other prognostic factors--a surrogate marker?

BACKGROUND

The number of mitoses and, thus, the proliferative capacity of a tumor is one of the most crucial variables for tumor grading. The Ki-67 nuclear antigen may be considered as an alternative to mitotic counts in grading schemes and as a single parameter that can be used in fine-needle aspirates and small biopsies.

METHODS

Immunohistochemistry using the anti-Ki-67 antibody MIB-1 was performed on 434 breast carcinoma specimens from the International Breast Cancer Study Group (formerly Ludwig) Trial V. Three groups based on Ki-67 percent were used to replace the mitotic counts component in the Nottingham grade (NHG) to produce the Nottingham/Ki-67 grade (NKG) and to assess Ki-67 as a single parameter.

RESULTS

In both the lymph node positive subgroup and the lymph node negative subgroup, the NKG and Ki-67 group was correlated significantly with Bloom-Richardson grade (BRG), NHG, and Nottingham type. Tumor size in the lymph node negative cohort and estrogen receptor status, progesterone receptor status, and c-erbB-2 expression in the lymph node positive cohort also were correlated significantly with NKG. Ki-67 percentage was correlated significantly with c-erbB-2 expression in the lymph node positive cohort only. NKG was similar to BRG and NHG when it was evaluated for prognostic significance. Patients with higher categoric Ki-67 percentages had worse overall and disease free survival in all groups except for the untreated, lymph node negative group.

CONCLUSIONS

Ki-67 detection represents a valuable tool and is a good objective substitute for mitotic counts when used in a grading system. When it is used alone, Ki-67 detection provides valuable information, although it is necessary to combine this with other parameters in the study of core biopsies and fine-needle aspirates.

Apolipoprotein E polymorphism and breast carcinoma: correlation with cell proliferation indices and clinical outcome

There is preliminary evidence that polymorphism of apolipoprotein E (apoE, protein; APOE, gene), one of the key regulatory proteins in cholesterol metabolism, influences the pathobiology of carcinoma of the colon, prostate and breast and also primary tumours of the brain. This study was designed to determine whether APOE polymorphism is related to variation in the rate of tumour cell proliferation and clinical outcome in carcinoma of the breast. One hundred and eleven infiltrating ductal carcinomas, for which follow up data were available, were included in the study. Estrogen and progesterone receptor status (ER, PR) cell proliferation index (MIB- 1) and APOE genotypes were determined from paraffin-embedded tissue by standard methods. Positive correlations were found between grade and tumour size, grade and presence of metastasis, grade and MIB-1 expression, as well as between ER and PR. Survival correlated inversely with tumour size and the presence of positive lymph nodes. Both steroid receptors correlated inversely with MIB- 1 expression. PR positive status also correlated inversely with high histological grade and presence of lymph node metastases. APOE allele frequencies resembled those of the general population. No significant associations were found between possession of either APOE epsilon2 or epsilon4 alleles and the parameters investigated. Although there is evidence to suggest that APOE epsilon4 may predispose to the development of carcinoma of the breast our data do not support the hypothesis that APOE genotype influences the rate of tumour cell proliferation or the clinical course.

Expression of interleukin 6 (IL-6) correlates with oestrogen receptor in human breast carcinoma

Multifunctional cytokines play important and only partially defined roles in mammary tumour development and progression. Normal human mammary epithelial cells constitutively produce interleukin 6 (IL-6), IL-8 and a non-secreted form of tumour necrosis factor. Transformation of mammary epithelial cells by different oncogenes is frequently associated with alterations of cytokine/growth factor production and responsiveness. In the present study we analysed the expression of IL-6 in 149 cases of invasive breast carcinoma and the data have been correlated with clinico-pathological variables including tumour size, histological grade, nodal status, and oestrogen and progesterone receptors, Ki67 and p53, protein expression. Though the majority of breast carcinomas expressed at least low levels of immunoreactive IL-6, we found that expression of this cytokine was inversely associated with histological tumour grade (P = 0.0017), but not with tumour size and nodal status. Ki67 positivity was inversely correlated with IL-6 expression (P = 0.027). Among biological parameters analysed, a direct association was found between the percentage of IL-6-positive cells and that of oestrogen (P = 0.00005) and progesterone (P = 0.025) receptor-positive cells. No correlation was observed between IL-6 and p53 protein expression. These data indicate that down-regulation of IL-6 is associated with highly malignant mammary carcinomas. It will be of interest to evaluate whether alterations of cytokines that are constitutively produced by mammary cells are also associated with high-grade tumours.