PTTG1 and non-small cell lung carcinoma: Secondly, many studies target the significance of single gene expression in NSCLC, especially oncogenes, such as cyclin B2 (CCNB2) [50], pituitary tumor transforming gene-1 (PTTG1) [51], and tumor suppressor gene as hedgehog-interacting protein (HHIP) [52].