A recent prospective French study involving 52,278 patients followed up between 1998 and 2006 has shown that at a CD4 count below 500 cells/mm3, the cancer risk (Hodgkin's lymphoma, liver and lung cancer) progressively increased: the highest risk was when CD4 count was below 50 cells/mm3 [9]. This evidence concerns the gene CD4 and lung carcinoma.