Our understanding about the molecular genetic alterations in sequential development of human cancers is limited. Our comprehensive approach will enable us to understand the cross talk between various pathways during the early development and progression of cancer. Hence, we have proposed the microarray based global transcriptomic analysis during sequential development of lung tumors in A/J mouse induced by B(a)P and NNK - potent carcinogens found in tobacco smoke. Chemoprevention or dietary and phytochemical intervention is emerging as an important modality for cancer prevention. Chemopreventive efficacy of polymeric black tea polyphenols (PBPs) has been established in various experimental models, although much remains to be elucidated in vivo to understand their molecular mechanism(s) of observed chemoprevention. Hence, we also plan to examine the molecular mechanism(s) of PBPs-mediated chemoprevention in vivo which may help in identification of several new molecular pathways and potential biomarkers that will be excellent intermediate end-points in monitoring disease progression, chemoprevention trials and validation of drug effect measurements.