HPRT1 and lung adenocarcinoma: Immunohistochemistry confirmed significant differences in the expression of HPRT1 between five tumor types (colon adenocarcinoma [COAD], head–neck squamous cell carcinoma [HNSC], lung adenocarcinoma [LUAD], thyroid carcinoma [THCA], uterine corpus endometrial carcinoma [UCEC]), and adjacent normal tissues (P < 0.05).