Treatment outcomes and unfavorable prognostic factors in patients with occult breast cancer.

AIMS: The purpose of this study was to evaluate the treatment outcomes and prognostic factors in patients with occult breast cancer (OBC). METHODS: We retrospectively analyzed 95 patients with OBC who were treated at our facility between January 1998 and June 2010. Of the 95 patients, 64 underwent mastectomy plus axillary lymph node dissection (ALND) with or without post-mastectomy radiation (Mast + ALND group), 13 underwent ALND followed by ipsilateral breast radiotherapy (BR + ALND group) and the remaining 18 were treated with ALND (ALND group). RESULTS: Patients who underwent Mast + ALND or BR + ALND had significantly improved rates of locoregional recurrence-free survival (LRFS) and recurrence/metastasis-free survival (RFS) than patients who only underwent ALND (p < 0.05). There were no significant differences in the LRFS (p = 0.718), RFS (p = 0.935) and breast cancer-specific survival (BCSS) (p = 0.991) rates between the patients who underwent Mast + ALND compared with those who received BR + ALND. Multivariate analysis revealed that patients with four or more involved lymph nodes had significantly worse outcomes (p = 0.042, HR = 4.63, 95% CI = 1.66-32.47 for BCSS and p = 0.038, HR = 3.62, 95% CI = 1.08-20.77 for RFS). CONCLUSIONS: Patients with OBC who received ALND and subsequent breast radiotherapy had similar outcomes to patients who underwent mastectomy. The presence of four or more involved lymph nodes may independently predict poor outcomes of OBC.

Inhibition of EGFR pathway signaling and the metastatic potential of breast cancer cells by PA-MSHA mediated by type 1 fimbriae via a mannose-dependent manner.

To identify more therapeutic targets and clarify the detailed mechanisms of Pseudomonas aeruginosa-mannose-sensitive hemagglutinin (PA-MSHA) on breast cancer cells both in vitro and in vivo. PA-MSHA was administered to epidermal growth factor receptor (EGFR)-positive human breast cancer cell lines MDA-MB-231HM and MDA-MB-468 in vitro and to mice bearing tumor xenografts. The mannose cocultured test was used to detect the effect of mannose on PA-MSHA-induced cell proliferation, cell cycle arrest, apoptosis, and EGFR pathway signaling. We found that cells stimulated with PA-MSHA exhibited a downregulation of EGFR signaling. The addition of mannose partially inhibited the PA-MSHA-stimulated cell anti-proliferative effect, cell apoptosis, cell cycle arrest, activation of apoptosis-associated caspases, and even downregulation of the EGFR signaling pathway. In vivo, PA-MSHA treatment significantly suppressed mammary tumorigenesis in xenografts in mice and decreased lung metastasis in MDA-MB-231HM cell-transplanted mice. Tumor sample analyses confirmed inhibition of the EGFR pathway in the PA-MSHA-treated mice. In conclusion, this study showed that the involvement of the mannose-mediated EGFR pathway has a critical function in the preclinical rationale for the development of PA-MSHA for the treatment of human breast cancer. It also suggests the potentially beneficial use of PA-MSHA in adjuvant therapy for breast tumors with EGFR overexpression.

Over expression of aromatase protein is highly related to MMPs levels in human breast carcinomas.

Estrogens can play a critical role in the development of breast cancer. Aromatase which catalyzes the formation of aromatic C18 estrogens from C19 androgens is regarded to be responsible for the cancer local production of estrogen. Studies not only from aromatase transfected breast cancer cells, but also transgenic mouse, which overexpressed aromatase, demonstrated that in situ produced estrogen plays more important roles than circulating estrogens in breast tumor promotion and progression. Matrix-metalloproteinases (MMPs) have been implicated in the proeolytic process, which play important roles in the aggressiveness of cancer cells including invasion of adjacent tissue and metastasis to distant sites. Expression of MMP2 and 9 may be stimulated by estrogens in hormonal dependent breast cancers, since tumor aromatase can stimulate breast cancer growth and progression in both an autocrine and a paracrine manner. Theoretically aromatase overexpression, that causes relatively high estrogen concentration in situ, may be positively related to MMP2 and 9 expression, indicate worse prognosis in breast cancers, and maybe insensitive to tamoxifen therapy. In the present study, we studied the expression of aromatase activity and MMPs in human breast carcinoma both in vitro and in vivo. In human breast carcinoma cell lines including MCF-7, MDA-MB-231 and MDA-MB-435, the expression of aromatase levels both in mRNA and protein activity was related to MMP2 and MMP9. In humam breast cancer samples, we demonstrated that aromatase expressions were strongly associated with MMP2 and MMP9 levels. It was interesting to observe that the positive relationship was only present in the ER and/or PR positive patients. This may indicate that both MMP2 and MMP9 were up regulated by estrogen produced by aromatase through ER. So in endocrine therapy, either blocking the ER by tamoxifen or inhibiting the aromatase by aromatase inhibitors for example letrozole, may both inhibit tumor growth and lower the metastatic potential especially in ER positive breast cancer patients by means of down-regulation of MMP2/9.