Subtipurile moleculare dezvoltate de carcinomul mamar lobular invaziv

Abstract

Abstract Background: Invasive lobular (ILC) and ductal (IDC) carcinoma are the two main histological subtypes of breast cancer. ILC are typically of low histological grade and mitotic index. It expresses estrogen and progesterone receptors (ER and PR) and rarely shows HER2 protein overexpression or amplification. These features suggest a good prognosis, yet some studies show that long-term outcomes of ILC are inferior to stage-matched IDC. Different molecular profiles developed by these two types of carcinoma, suggests different subtypes, which could have different outcomes. The aim of present study was the establishment of molecular subtypes developed by invasive lobular carcinomas. Material and methods: there were examined primary tumors of 18 patients with lobular invasive carcinoma, using conventional histological and immunohistochemical techniques. By Leica Bond-Max (Leica Microsystems GmbH, Wetzlar, Germany) autostainer we determined the expression of ER, PR, HER2, CK5 and Ki67 receptors, which have been clustered into molecular subtypes in accordance with StGallen, 2013 recommendations. Results: ILC developed Luminal subtypes in 14 cases/77,8%. Luminal B/Ki67 subtype was determined in 8 cases/44,4%, Luminal A in 5 cases/27,8% and single tumors showed Luminal B/HER2, 5NP and Basal-like characteristics. Two tumors were described as HER2 positive. Conclusions: Luminal B/Ki67 subtype is the most frequent profile developed by invasive lobular carcinoma. These findings suggest high aggressivity and bad prognosis.