I. To describe changes in protein and mRNA levels of ribonucleotide reductase M1 (RRM1), thymidylate synthetase (TS), and excision repair cross-complementing rodent repair deficiency, complementation group 1 (ERCC1) in serial biopsies obtained from patients being treated with gemcitabine (gemcitabine hydrochloride), pemetrexed (pemetrexed disodium), and platinum.