Phenotypic characterization of disseminated cells with TSC2 loss of heterozygosity in patients with lymphangioleiomyomatosis

Am J Respir Crit Care Med. 2010 Dec 1;182(11):1410-8. doi: 10.1164/rccm.201003-0489OC. Epub 2010 Jul 16.


Rationale: Lymphangioleiomyomatosis (LAM), occurring sporadically (S-LAM) or in patients with tuberous sclerosis complex (TSC), results from abnormal proliferation of LAM cells exhibiting mutations or loss of heterozygosity (LOH) of the TSC genes, TSC1 or TSC2.

Objectives: To identify molecular markers useful for isolating LAM cells from body fluids and determine the frequency of TSC1 or TSC2 LOH.

Methods: Candidate cell surface markers were identified using gene microarray analysis of human TSC2⁻(/)⁻ cells. Cells from bronchoalveolar lavage fluid (BALF), urine, chylous effusions, and blood were sorted based on reactivity with antibodies against these proteins (e.g., CD9, CD44v6) and analyzed for LOH using TSC1- and TSC2-related microsatellite markers and single nucleotide polymorphisms in the TSC2 gene.

Measurements and main results: CD44v6(+)CD9(+) cells from BALF, urine, and chyle showed TSC2 LOH in 80%, 69%, and 50% of patient samples, respectively. LAM cells with TSC2 LOH were detected in more than 90% of blood samples. LAM cells from different body fluids of the same patients showed, in most cases, identical LOH patterns, that is, loss of alleles at the same microsatellite loci. In a few patients with S-LAM, LAM cells from different body fluids differed in LOH patterns. No patients with S-LAM with TSC1 LOH were identified, suggesting that TSC2 abnormalities are responsible for the vast majority of S-LAM cases and that TSC1-disease may be subclinical.

Conclusions: Our data support a common genetic origin of LAM cells in most patients with S-LAM, consistent with a metastatic model. In some cases, however, there was evidence for genetic heterogeneity between LAM cells in different sites or within a site.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, N.I.H., Intramural

MeSH terms

  • Biomarkers / metabolism
  • Bronchoalveolar Lavage Fluid
  • Chyle / metabolism
  • Female
  • Genetic Markers / genetics
  • Genetic Predisposition to Disease / genetics
  • Humans
  • Loss of Heterozygosity / genetics*
  • Lymphangioleiomyomatosis / genetics*
  • Lymphangioleiomyomatosis / metabolism
  • Polymerase Chain Reaction / methods
  • Polymorphism, Single Nucleotide / genetics
  • Protein Array Analysis / methods
  • Reproducibility of Results
  • Tuberous Sclerosis Complex 2 Protein
  • Tumor Suppressor Proteins / genetics*
  • Tumor Suppressor Proteins / metabolism


  • Biomarkers
  • Genetic Markers
  • TSC2 protein, human
  • Tuberous Sclerosis Complex 2 Protein
  • Tumor Suppressor Proteins