As an alternative approach to determine the clinical significance of HLA-G and SPAG9 on BM predisposition in primary lung tumors, we queried gene chip and RNA-seq lung tumor datasets through the KMplotter portal (52, 53) to determine whether HLA-G and SPAG9 expression in primary lung tumors predicts poor patient survival; since, a large percentage (20 to 50%) of lung cancer patients develop BM, which correlates with limited survival in affected patients (54). This evidence concerns the gene SPAG9 and lung cancer.