“…Moreover, it is hoped that, as for some biological factors in other human tumour types (Paradiso et al, 1993;Amadori et al, 1994), predictors of response to different systemic treatments will also be identified in lung cancer. DNA ploidy, cell proliferation, and products of oncogenes or tumour-suppressor genes in lung cancer have been extensively investigated (Volm et al, 1985;Alama et al, 1990;Isobe et al, 1990;Miyamoto et al, 1991;Silvestrini et al, 1991;Tungekar et al, 1991;Filderman et al, 1992;McLaren et al, 1992;Quinlan et al, 1992;M0rkve et al, 1993;Scagliotti et al, 1993;Ebina et al, 1994;Passlick et al, 1994). However, consistent results have not been achieved, probably owing to the heterogeneity in terms of stage and treatment in case series analysed, which implies interference of confounding factors.…”