Previous studies have shown that PTEN is aberrantly downregulated and acts as a tumor suppressor in several types of cancer, and that PTEN loss is an unfavorable factor in predicting the outcomes of cancer [41], colorectal cancer [42], non-small cell lung cancer [43], diffuse large B-cell lymphoma [44], mesothelioma [45], and prostate cancer [46]. The gene discussed is PTEN; the disease is colorectal cancer.