Clinicopathologic Characteristics Of Microinvasive Carcinoma And Progression Of Ductal Carcinoma In Situ To Invasive Breast Cancer

ObjectiveWe evaluated the clinicopathologic characteristics, molecular features and clinical outcome of microinvasive carcinoma and ductal carcinoma in situ(DCIS).We investigated the EMT phenotypes and myoepithelial may be involved in the progression from in situ to invasive breast cancer. MethodsOne hundred and thirty one microinvasive carcinoma and 451 DCIS cases were collected. ER, PR, HER2, and Ki67 were examined by immunohistochemistry in pathological sections. We assessed the clinicopathologic characteristics, molecular features and clinical outcome of microinvasion and compared to those of DCIS.We investigated the expression of EMT and myoepithelial phenotypic markers in DCIS and IDC. Stimulation with TGF-β1 induced EMT in MCF-7 and then in co-culture conditions with MDA-MB-231. Cell morphological changes were observed. Real-time quantitative PCR and Western blot were determined the expression level of EMT marker. Cell proliferation assay was used MTT assay. Scratch wound-healing assay and Transwell were demonstrated the migration capacity. ELISA was used to determine the concentration of MMP-9 and IL-6. Results1、Aggressive features like larger tumor size and more LN metastases were associated with microinvasive carcinoma. There was no distinguished difference in age, menopausal status, family history, endocrine therapy, hormone receptors or subtype between microinvasive carcinoma and DCIS. The clinicopathological characteristics among the subtypes of microinvasive carcinoma were compared. Higher histological grade was associated with HER2-enriched and TNBCs. There was no difference in other factors among different subtypes. Older patients, larger tumor size, higher nuclear grade and postmenopausal status were associated with HER2-enriched and TNBCs in DCIS. There was no difference in lymph node status or family history.2、The 5-year OS rates for microinvasive carcinoma and DCIS patients were 99.0% and 99.2%, respectively. The 5-year DFS rates for microinvasion and DCIS patients were 95.2% and 95.9%, with a median follow-up of 69 and 62 months, respectively. There was no difference in outcome with or without microinvasion.3、When comparing the expression of EMT markers among normal tissue, DCIS and IDC, expression of N-cadherin, Snail, Vimentin, Twist and Zeb1 and loss of E-cadherin were significantly higher in IDC.4、When comparing the expression of myoepithelial markers among normal tissue, DCIS and IDC, expression of SMA, p63, and calponin were positive in DCIS and its adjacent normal breast tissue. None of the IDC expressed SMA, p63, and calponin.5、Stimulation with TGF-β1 in MCF-7 changed the morphology of the cells. Stimulation with TGF-β1 greatly reduced the mRNA level and protein expression of E-cadherin and effectively increased the expression levels for the mesenchymal markers N-cadherin and Vimentin in MCF-7. MTT assay was neither suppressed nor increased. Stimulation with TGF-β1 in MCF-7 significantly enhanced the migration of cells.6、Stimulation with TGF-β1 in co-culture conditions, MDA-MB-231 develop into mesenchymal-like cells. MTT assay was neither suppressed nor increased by stimulation with TGF-β1. In co-culture conditions, TGF-β1 significantly enhanced the migration and invasion of MDA-MB-231 compared with control cells. Stimulation with TGF-β1 greatly increased the concentration of MMP-9 and IL-6.ConclusionThe clinicalpathologic features and outcomes of microinvasion seem to be equivalent to DCIS. Expression of mesenchymal markers, loss of E-cadherin, and decreased myoepithelial phenotypic markers are greater in invasive carcinomas than in DCIS. TGF-β1 might have an important role in regulating the expression of epithelial and mesenchymal markers during EMT in breast cancer. EMT phenotypes and myoepithelial may be involved in the progression from in situ to invasion.