Extrarenal perivascular epithelioid cell tumors (PEComas) respond to mTOR inhibition: clinical and molecular correlates

Int J Cancer. 2013 Apr 1;132(7):1711-7. doi: 10.1002/ijc.27800. Epub 2012 Sep 21.

Abstract

Perivascular epithelioid cell tumors (PEComas) are a group of rare mesenchymal tumors that typically show both melanocytic and smooth muscle cell features. Some types of PEComa are seen at high frequency in tuberous sclerosis complex (TSC). The TSC1 and TSC2 genes are commonly mutated in both TSC-associated and sporadic PEComas, and mTOR signaling pathway activation is also common in these tumors. Preliminary reports have indicated that the mTOR inhibitors sirolimus and related drugs have activity in some patients with non-TSC-associated PEComa. Here, we report on the use of these medications in the treatment of five consecutive patients with extrarenal nonpulmonary PEComas seen at one institution. Three complete responses, one partial response and one case of progression were seen. Molecular studies identified TSC2 aberrations in four of these patients, and TFE3 translocation was excluded in the resistant case. A review of all published cases as well as those reported here indicates that partial or complete response was seen in 6 of 11 PEComas, with 5 of 6 having a complete response. These findings highlight the consistent though incomplete activity of mTOR inhibitors in the treatment of PEComas.

Publication types

  • Case Reports
  • Research Support, N.I.H., Extramural

MeSH terms

  • Adrenal Gland Neoplasms / drug therapy*
  • Adrenal Gland Neoplasms / genetics
  • Adrenal Gland Neoplasms / pathology
  • Adult
  • Aged
  • Antibiotics, Antineoplastic / therapeutic use
  • Everolimus
  • Female
  • Humans
  • Immunoenzyme Techniques
  • Immunosuppressive Agents / therapeutic use
  • In Situ Hybridization, Fluorescence
  • Loss of Heterozygosity
  • Male
  • Middle Aged
  • Mutation / genetics
  • Perivascular Epithelioid Cell Neoplasms / drug therapy*
  • Perivascular Epithelioid Cell Neoplasms / genetics
  • Perivascular Epithelioid Cell Neoplasms / pathology
  • Prognosis
  • Remission Induction
  • Retroperitoneal Neoplasms / drug therapy*
  • Retroperitoneal Neoplasms / genetics
  • Retroperitoneal Neoplasms / pathology
  • Review Literature as Topic
  • Sirolimus / analogs & derivatives*
  • Sirolimus / therapeutic use*
  • TOR Serine-Threonine Kinases / antagonists & inhibitors*
  • TOR Serine-Threonine Kinases / genetics
  • TOR Serine-Threonine Kinases / metabolism
  • Tuberous Sclerosis Complex 1 Protein
  • Tuberous Sclerosis Complex 2 Protein
  • Tumor Suppressor Proteins / genetics

Substances

  • Antibiotics, Antineoplastic
  • Immunosuppressive Agents
  • TSC1 protein, human
  • TSC2 protein, human
  • Tuberous Sclerosis Complex 1 Protein
  • Tuberous Sclerosis Complex 2 Protein
  • Tumor Suppressor Proteins
  • Everolimus
  • MTOR protein, human
  • TOR Serine-Threonine Kinases
  • Sirolimus