Defective expression of FasL and Baxin human lung cancer

Abstract. The present studies investigated whether FasL and Baxgenes are expressed in pleuro-pulmonary biopsies from patientswith lung cancer. FasL, Bax, and TNF mRNAs were detected in 19biopsies of primary or metastasic lung cancer by fluorescent insitu hybridization assays. Fluorescent probes were produced bypolymerase chain reaction using a human spleen lambda gt11library and specific primers for FasL, Bax, and TNF. Proteinswere detected by immunohistochemistry using monoclonal anti-FasL, anti-Bax, and anti-TNF antibodies. Chromatinfragmentation was detected by TUNEL. Seven negative samples fromsubjects without lung pathology were obtained during legalautopsies and 12 positive control biopsies from patients withlung infections were also included. Sixty-eight percent of lungcancer biopsies exhibited FasL; Bax was expressed in 68% andTNF in 63%. FasL protein was detected in 21%, Bax protein in26%, and TNF was present in 31% of cancer biopsies. A lowdegree of apoptosis in lung cancer was demonstrated by TUNELassays. A defect in FasL, Bax, and TNF gene expression wasfound in lung cancer biopsies. Some tumors normally expressedthe mRNA of FasL, Bax, or TNF, but their proteins were absent,or were non-functional, since TUNEL assays were negative. Such afailure would contribute to cancer cell survival anddissemination.