The results showed that high MTHFD2 expression levels were usually indicative of a poorer prognosis in most cancer types except for cervical squamous cell carcinoma and endocervical adenocarcinoma, cholangiocarcinoma, colon adenocarcinoma, glioblastoma multiforme, lung squamous cell carcinoma, ovarian cancer, stomach adenocarcinoma, and thyroid carcinoma (Figure 2). This evidence concerns the gene MTHFD2 and squamous cell lung carcinoma.