Analysis of PIK3CA exon 9 and 20 mutations in breast cancers using PCR-HRM and PCR-ARMS: Correlation with clinicopathological criteria

作者：Harle Alexandre^*; Lion Maeva; Lozano Nicolas; Husson Marie; Harter Valentin; Genin Pascal; Merlin Jean Louis

来源：Oncology Reports, 2013, 29(3): 1043-1052.

DOI：10.3892/or.2013.2229

• PIK3CA mutations
• breast cancer
• PCR-high resolution melting assay
• PCR-amplification refractory mutation system

Phosphatidylinositol-3-kinases (PI3K) are essential for cell signaling, proliferation, differentiation and survival. The catalytic subunit of PI3K, encoded by the PIK3CA oncogene, is mutated in 18-45% of breast carcinomas. These mutations, involved in tumorigenic processes, activate the PI3K/AKT/mTOR signaling pathway. Resistance to anti-human epidermal growth factor receptor, hormonal or anti-PI3K therapies have been described in breast carcinomas bearing activation of the PI3K signaling pathway. The present study reports the evaluation of PIK3CA exon 9 and 20 mutations in 149 invasive breast cancer cases using a validated PCR-high resolution melting assay (PCR-HRM). An amplification refractory mutation system (PCR-ARMS) using allele-specific scorpion primers was used to detect hotspot mutations in exons 9 (c.1624G -%26gt; A and c.1633G -%26gt; A) and 20 (c.3140A -%26gt; G and c.3140A -%26gt; T) in 118 tumor specimens. No correlation was observed with age at diagnosis, histological type, hormone receptor and HER2 status. PIK3CA exon 9 and 20 mutations were found to be related to Scarff-Bloom-Richardson (SBR) grade with a lower rate of mutations and a higher frequency of exon 9 mutations in SBRI and exon 20 mutations in SBRII/III tumors. No difference was observed in the incidence rates of the two different mutations screened for each exon in any subcategory. A statistically significant correlation was found between PCR-HRM and PCR-ARMS (kappa=0.845; P%26lt;0.001). PCR-ARMS was found to be more sensitive than PCR-HRM (sensitivity 0.5 and 5-10% of mutated DNA, respectively). We propose that PCR-HRM and PCR-ARMS can be combined for the cost-effective routine clinical identification of PIK3CA mutations for the purpose of personalizing therapy for invasive breast cancers.

• 出版日期2013-3