Invasive micropapillary mucinous carcinoma of the breast is associated with poor prognosis

Abstract

Invasive micropapillary carcinoma (IMPC) of the breast is a highly aggressive breast cancer. Polarity reversal exemplified by cluster growth is hypothesized to contribute to the invasiveness and metastasis of IMPC. In this study, we demonstrate that levels of β1 integrin and Rac1 expression were greater in breast IMPC than in invasive breast carcinoma of no specific type and paraneoplastic benign breast tissue. We show that silencing β1 integrin expression using the β1 integrin inhibitor AIIB2 partially restored polarity in IMPC primary cell clusters and downregulated Rac1. Thus, overexpression of β1 integrin upregulates Rac1. Univariate analysis showed that overexpression of β1 integrin and Rac1 was associated with breast cancer cell polarity reversal, lymph node metastasis, and poor disease-free survival in IMPC patients. Multivariate analysis revealed that polarity reversal was an independent predictor of poor disease-free survival. These findings indicate that overexpression of β1 integrin and the resultant upregulation of Rac1 contribute to polarity reversal and metastasis of breast IMPC, and that β1 integrin and Rac1 could be potential prognostic biomarkers and targets for treatment of breast IMPC. www.impactjournals.com/oncotarget/

Prognosis of subtypes of the mucinous breast carcinoma in Chinese women: a population-based study of 32-year experience (1983-2014)

“…Poorer survival was also observed for breast carcinoma containing IMPC component [22]. Notably, a special subtype of PMBC with micropapillary epithelial growth pattern was identified as invasive micropapillary mucinous carcinoma (IMPMC) [23], or mucinous carcinomas with a micropapillary pattern (MUMPC) [24]. This heterogeneous PMBC had more LN metastasis, higher Her2 expression, LVI, and a poorer prognosis than pure PMBC [23, 24].…”

Invasive Micropapillary Carcinoma of the Breast: An Update

“…For diagnosis, the micropapillary architecture should constitute more than 50% of the tumor epithelial components. Liu et al 36 reviewed 531 cases of archived PMC and found 134 cases (25.23%) with IMPC components that justified a diagnosis of IMMPC (Figure 2, A through C). Compared with PMC without an IMPC component, IMMPC was found more frequently in younger patients and in tumors with increased LNM and LVI and human epidermal growth factor receptor 2 (HER2/neu) positivity (protein overexpression or gene amplification).…”

Diagnostic dilemma of micropapillary variant of mucinous breast cancer

“…In contrast to pure mucinous carcinoma, MpVMBC tended to have LVI and a higher likelihood for nodal metastasis8 in up to 60%2 and 35.1%4 of cases, respectively. HER2 overexpression was also more frequent4 with up to 20% reported 2.…”

“…HER2 overexpression was also more frequent4 with up to 20% reported 2. As a result, MpVMBC had been associated with a poorer prognosis compared with pure mucinous cancer,2 4 with the presence of micropapillary architecture being an independent adverse prognostic factor.…”