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BioMed Research International
Volume 2014, Article ID 810487, 7 pages
http://dx.doi.org/10.1155/2014/810487
Research Article

Oncogenic PIK3CA Mutation and Dysregulation in Human Salivary Duct Carcinoma

1The Department of Pathology, Columbia University Medical Center, 1130 Saint Nicholas Avenue, ICRC 10-04, New York, NY 10032, USA
2Herbert Irving Comprehensive Cancer Center, Columbia University Medical Center, 1130 Saint Nicholas Avenue, ICRC 10-04, New York, NY 10032, USA
3The Department of Otolaryngology and Head and Neck Surgery, Columbia University Medical Center, 1130 Saint Nicholas Avenue, ICRC 10-04, New York, NY 10032, USA

Received 29 October 2013; Revised 12 December 2013; Accepted 21 December 2013; Published 8 January 2014

Academic Editor: Sandra B. Gabelli

Copyright © 2014 Wanglong Qiu et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Salivary duct carcinoma (SDC) is an aggressive malignant tumor with a high mortality, which resembles high-grade breast ductal carcinoma in morphology. The parotid gland is the most common location. Its molecular genetic characteristics remain largely unknown. We have previously reported high incidence of PIK3CA somatic mutations in head and neck squamous cell carcinoma, particularly in pharyngeal cancers. Here we examined the PIK3CA gene expression status and hotspot mutations in six cases of SDC by immunohistochemistry and genomic DNA sequencing. Immunohistochemistry showed that PIK3CA expression was elevated in all six patients with SDC. By DNA sequencing, two hotspot mutations of the PIK3CA gene, E545K (exon 9) and H1047R (exon 20), were identified in two of the six cases. Our results support that oncogenic PIK3CA is upregulated and frequently mutated in human SDC, adding evidence that PIK3CA oncogenic pathway is critical in the tumorigenesis of SDC, and may be a plausible drug target for this rare disease.