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PIK3CA in Breast Carcinoma: A Mutational Analysis of Sporadic and Hereditary Cases

Michelucci, Angela PhD*; Di Cristofano, Claudio MD* †; Lami, Azzurra PhD*; Collecchi, Paola PhD*; Caligo, Adelaide PhD*; Decarli, Nicola MD*; Leopizzi, Martina PhD; Aretini, Paolo PhD*; Bertacca, Gloria PhD*; Porta, Romana Prosperi MD; Ricci, Sergio MD; Rocca, Carlo Della MD; Stanta, Giorgio MD§; Bevilacqua, Generoso MD*; Cavazzana, Andrea MD* ∥

Diagnostic Molecular Pathology: December 2009 - Volume 18 - Issue 4 - pp 200-205
doi: 10.1097/PDM.0b013e31818e5fa4
Original Articles

The PI3K-Akt cascade is a key signaling pathway involved in cell proliferation, survival, and growth. Activating PIK3CA mutations have been reported in breast carcinoma (BC). The aim of this study was to characterize the PIK3CA mutations at exons 9 and 20 in a series of 176 sporadic and 22 hereditary BCs and to correlate the results with clinicopathologic parameters and survival. In sporadic BC, 68 missense mutations were detected. PIK3CA mutations were significantly associated with ER+ in HER2-negative cases. A higher frequency of PIK3CA mutations was present in lobular carcinoma compared with ductal carcinoma (50% vs. 35%). There was no association between the survival and PIK3CA mutational status. In hereditary BC, PIK3CA mutations were found only in the BRCA2 group. The PIK3CA mutation seems to characterize the luminal-type BC, in both sporadic and BRCA2 mutated forms, and is absent in the basal-type BC, in both the sporadic and BRCA1 mutated forms.

*Division of Surgical, Molecular and Ultrastructural Pathology, Department of Oncology

Department of Oncology, Medical Oncology Unit, University of Pisa and University Hospital of Pisa

Department of Experimental Medicine, Sapienza University of Rome, Polo Pontino, I.C.O.T, Latina

§Department of Clinical, Morphological and Technological Sciences, University of Trieste

Surgical Pathology Unit, ASL1 Massa-Carrara, Tuscany, Italy

Reprints: Claudio Di Cristofano, MD, Department of Experimental Medicine, Sapienza University of Rome, Polo Pontino, I.C.O.T, Via F. Faggiana, 34 0400, Latina, Italy (e-mail:

© 2009 Lippincott Williams & Wilkins, Inc.