BACKGROUNDTo investigate the expression of phosphatase and tensin homology deleted on chromosome ten (PTEN) and FasL proteins and their correlation in human small cell lung cancer (SCLC).

METHODSExpression of PTEN and FasL proteins was examined in forty-two paraffin-embedded SCLC samples and sixteen pulmonary benign disease tissues by SP immunohistochemical technique.

RESULTSLoss rate of PTEN protein in 42 SCLC tissues (73.8%) was significantly higher than that in 16 pulmonary benign disease tissues (0%) (P < 0.01). The loss of PTEN protein was related to TNM stages (P < 0.01), but not to cellular subtype and sex and age of patients (P > 0.05). FasL expression rate in 42 SCLC tissues (50.0%) was remarkably higher than that in 16 pulmonary benign disease tissues (12.5%) (P < 0.05). The expression level of FasL in PTEN-positive SCLC tissues was significantly lower than that in PTEN-negative SCLC tissues (P < 0.01).

CONCLUSIONSLoss of PTEN expression may play a role in the occurrence and development of SCLC. There is an up-regulated expression of FasL protein in SCLC. The deletion of PTEN protein may be related to the high expression of FasL protein.