Molecular alterations differentiate microinvasive carcinoma from ductal carcinoma in situ and invasive breast carcinoma: retrospective analysis of a large single-center series

Int J Clin Exp Pathol. 2021 Aug 15;14(8):892-901. eCollection 2021.ABSTRACTMicroinvasive carcinoma (MIC) of the breast is a rare lesion. The clinicopathologic features and biologic behavior of MIC are unclear. Whether MIC is a distinct entity or an interim stage in the progression from ductal carcinoma in situ (DCIS) to invasive breast carcinoma (IBC) remains to be determined. A retrospective review of clinicopathologic features and analysis of the expression of estrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor receptor 2 (HER-2), and Ki-67 in patients with MIC (90 cases), DCIS (268 cases) and IBC (1504 cases) was performed. Most MICs (93.3%) exhibited an intermediate to high nuclear grade, and this proportion was larger than that of DCIS (62.7%, P < 0.001) or IBC (85.4%, P = 0.036). The incidence of sentinel lymph node metastasis in MIC (12.5%) was higher than that of DCIS (1.6%, P < 0.001), but much lower than that of IBC (39.7%, P < 0.001). MICs had higher expression of HER-2 and lower expression of ER and PR compared to DCIS and IBC; and MIC was more likely to present with a HER-2+ subtype. Furthermore, DCIS exhibited greater HER-2 overexpression or gene amplification (P < 0.001) levels and lower proliferation index of Ki-67 (P < 0.001) compared to IBC. Our results suggest that the clinicopathologic and molecular phenotype of MIC are different from DCIS and IBC. Thus, MIC may be a distinct entity rather than an interim stage ...
Source: International Journal of Clinical and Experimental Pathology - Category: Pathology Authors: Source Type: research