Interleukin-10 expression is correlated with growth fraction in human non-small cell lung cancer xenografts

We examined IL-10 and IL-10 receptor (IL-10R) gene expression in 44 xenografts of human non-small cell lung cancer (NSCLC) by reverse transcription-polymerase chain reaction (RT-PCR) assay with human-specific primers. IL-10 gene expression was detected in 10 (22.7%) of 44 xenografts (0/11 adenocarcinomas, 6/19 squamous cell carcinomas, 4/14 large cell carcinomas) and IL-10R expression in 8 (18.2%) xenografts. The IL-10-positive xenografts immunohistochemically showed significantly increased growth fractions of neoplastic cells (471.0 +/- 112.2) relative to IL-10-negative xenografts (208.4 +/- 96.3) (p=0.009, Mann-Whitney U test), and showed significantly increased vascular number (p=0.008, Mann-Whitney U test). These results suggested that IL-10 expression is correlated with growth features in human NSCLC.