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Microsatellite Instability Is Uncommon in Lymphoepithelioma-like Carcinoma of the Lung

Sanja Dacic MD, PhD, Deren Lomago, Jennifer L. Hunt MD, Antonia Sepulveda MD, PhD, Samuel A. Yousem MD
DOI: http://dx.doi.org/10.1309/CRCU356U7146YC31 282-286 First published online: 1 February 2007

Abstract

Primary lymphoepithelioma-like carcinoma of the lung (LELC) shares some morphologic and clinical characteristics with malignancies associated with microsatellite instability (MSI). The aims of our study were to determine the MSI status in LELC and compare these findings with stage I non–small cell lung carcinoma (NSCLC) with marked lymphocytic host response (MLHR). We assessed MSI by a DNA-based polymerase chain reaction assay using mononucleotide (BAT25 and BAT26) and dinucleotide (D2S123, D5S346, and D17S250) repeats. MSI was detected in 2 (29%) of 7 LELC cases with only 1 marker (D17S250), and in 3 (19%) of 16 NSCLC cases with MLHR with only 2 markers (1 D2S123 and 2 D17S250). Loss of heterozygosity (LOH) was detected at 1 or 2 of 3 dinucleotide repeats in 11 NSCLC cases (69%) with MLHR and 3 LELC cases (43%) (P = .36). The overall frequencies of LOH in NSCLC with MLHR were 29% and 19% in LELC (P = .55). MSI is very uncommon in LELC, indicating that MSI is not an important event in carcinogenesis for this tumor subtype. The presence of LOH suggests a probable role of tumor suppressor genes in LELC carcinogenesis.

Key Words:
  • Lymphoepithelioma-like carcinoma
  • Lung
  • Microsatellite instability
  • Loss of heterozygosity