Mutations of PIK3CA are rare in cutaneous melanoma

Melanoma Res. 2006 Apr;16(2):197-200. doi: 10.1097/01.cmr.0000200488.77970.e3.

Abstract

Recent studies have shown that the PIK3CA gene, which encodes the p110alpha catalytic subunit of phosphatidylinositol 3-kinases, is mutated in human cancers. To determine whether PIK3CA is altered in cutaneous melanoma, we screened a series of 101 melanoma metastases. We identified PIK3CA missense mutations in three metastases (3%). Interestingly, these mutations were observed only in tumours that were negative for NRAS mutations. Using immunohistochemistry, we also analysed our metastases for the expression of phosphorylated Akt. These analyses revealed a moderate to strong phosphorylated Akt expression in 78% (21 of 27) of metastases with NRAS mutations and in 73% (54 of 74) of metastases without NRAS mutations. Interestingly, the three metastases with mutations in PIK3CA all exhibited a strong expression of phosphorylated Akt. Taken together, our results show that PIK3CA is mutated in a minority of melanomas and suggest that mutations in this gene may represent an alternative mechanism of Akt activation in cutaneous melanoma.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Class I Phosphatidylinositol 3-Kinases
  • DNA Mutational Analysis
  • Female
  • Humans
  • Immunohistochemistry
  • Male
  • Melanoma / genetics*
  • Melanoma / secondary
  • Mutation, Missense
  • Oncogene Protein v-akt / metabolism
  • Phosphatidylinositol 3-Kinases / genetics*
  • Phosphorylation
  • Polymerase Chain Reaction
  • Polymorphism, Single-Stranded Conformational
  • Skin Neoplasms / genetics*
  • Skin Neoplasms / pathology

Substances

  • Phosphatidylinositol 3-Kinases
  • Class I Phosphatidylinositol 3-Kinases
  • PIK3CA protein, human
  • Oncogene Protein v-akt