The inducible heat shock protein (HSP)72 plays a central role in antitumor immunomodulation. HSP72 expression was assessed on tumor samples of 43 patients with advanced and metastatic small cell lung cancer (SCLC) by immunohistochemistry and HSP72 [HSPA1B A(1267)G] polymorphism was determined. HSP72 expression of SCLC cells was significantly decreased in GG as compared to cells of AA or AG genotype patients, and was associated with significantly shorter survival in GG patients as compared to carriers of the A allele. Decreased HSP72 expression of SCLC cells associated with HSP72 GG genotype is a negative prognostic factor for survival in SCLC patients.