FHIT and lung cancer: A549 lung cancer-derived cells, expressing low-level endogenous Fhit, and susceptible to apoptosis on exogenous Fhit expression11, were infected with AdFHIT or AdFHIT-His624 and treated with dithiobis(succinimidyl propionate (DSP)), a cross-linker that crosses membranes and fixes proteins in complex in vivo.