Breast, colon, lung and prostate cancer are four of the most common causes of cancer in the United States, are major causes of cancer cell death, and were examined.[64] Two cell lines for each cancer type were assessed: A549 (adenocarcinoma) and H226 (squamous carcinoma) for lung, MCF-7 (estrogen receptor [ER] positive) and MDA-MB-231 (ER negative) for breast, LNCaP (androgen receptor [AR] positive) and PC3-M (AR negative) for prostate, and HCT116 (wild type p53, mutated KRAS) and HT29 (p53 mutant) for colon.[65]. The gene discussed is KRAS; the disease is prostate cancer.