Relationship of p53, Bcl-2, Ki-67 index and E-cadherin expression in early invasive breast cancers with comedonecrosis as an accelerated apoptosis

Relationship of Ki-67 index in biopsies of metastatic breast cancer tissue and circulating tumor cells (CTCs) at the time of biopsy collection

BACKGROUND

The proliferation marker Ki-67 is a major pathological feature for the description of the state of disease in breast cancer. It helps to define the molecular subtype and to stratify between therapy regimens in early breast cancer and helps to assess the therapy response. Circulating tumor cells (CTCs) are a negative prognostic biomarker for progression free (PFS) and overall survival (OS) in patients with metastatic breast cancer. Therefore, the CTC count is often described as surrogate for the tumor burden. Both, decrease of Ki-67 and CTC count are considered as evidence for therapy response. The presented work analyzed the correlation between the Ki-67 indices of metastatic tissue biopsies and CTC counts in biopsy time-adjacent peripheral blood samples.

PATIENTS AND METHODS

Blood samples from 70 metastatic breast cancer patients were obtained before the start of a new line of systemic therapy. CTCs were enumerated using CellSearch® (Menarini Silicon Biosystems, Bologna, Italy) whereas intact CTCs (iCTCs) and non-intact or apoptotic CTCs (aCTCs) were distinguished using morphologic criteria. The proportion of cells expressing Ki-67 was evaluated using immunohistochemistry on biopsies of metastases obtained concurrently with CTC sampling before the start of a new line of systemic therapy.

RESULTS

65.7% of patients had a Ki-67 index of > 25%. 28.6% of patients had ≥ 5, 47.1% ≥ 1 iCTCs. 37.1% had ≥ 5, 51.4% ≥ 1 aCTCs. No correlation was shown between Ki-67 index and iCTC and aCTC count (r = 0.05 resp. r = 0.05, Spearman's correlation index). High CTC-counts did not coincide with high Ki-67 index. High Ki-67, ≥ 5 iCTCs and aCTCs are associated with poor progression free (PFS) and overall survival (OS).

CONCLUSION

CTCs and Ki-67 are independent prognostic markers in metastatic breast cancer. High Ki-67 in metastatic tumor tissue is not correlated to high iCTC or aCTC counts in peripheral blood.

Tamoxifen and ICI 182,780 increase Bcl-2 levels and inhibit growth of breast carcinoma cells by modulating PI3K/AKT, ERK and IGF-1R pathways independent of ERalpha

We recently showed that estrogen withdrawal from the ERalpha(+), high Bcl-2-expressing breast carcinoma cells (MCF-7B) reduced Bcl-2 protein levels while increasing cell-cell adhesion, and junction formation. Here we compared these cells with the ERalpha(+) and low Bcl-2-expressing MCF-7 cells and with the normal mammary epithelial cell line MCF-10-2A not expressing ERalpha or Bcl-2. All cell lines expressed normal HER2. Antiestrogen (Tamoxifen and ICI 182,780) treatment increased Bcl-2 levels in both MCF-7 and -7B cells and led to the formation of acinar structures. This treatment led to the dissociation of junctions and redistribution of junctional components to the cytoplasm in MCF-10-2A and -7 cells, while in MCF-7B cells junctional proteins redistributed to membranes. Antiestrogen treatment decreased PI3K/Akt activation and increased ERK activation regardless of ERalpha status. IGF-1R was inactivated in the antiestrogen-treated MCF-7 cells while it was activated in MCF-7B cells. Our data show that Tamoxifen and ICI 182,780 can induce growth inhibitory effects via the sustained activation/inactivation of signaling pathways that regulate cell survival, cell death and differentiation in the absence of ERalpha. Furthermore, Bcl-2 overexpression may alter the functional interactions among these pathways in response to antiestrogens, which also may provide a potential explanation for the observation that Bcl-2 overexpressing tumors have a better prognosis.