SPAG4 and cancer: As expected, the acid adaptation and tumor-upregulated genes that were associated with poor prognosis (Figure 6A, top list) included multiple genes related to ECM and cell motility in various cancers, such as those encoding sperm-associated antigen-4 (SPAG4) [50], microfibril-associated protein-2 (MFAP2) [51], the ADAM protease ADAMTSL4 [52], and ECM components heparan-sulfate proteoglycan-2 (HSPG2) and Procollagen C-Endopeptidase Enhancer 2 (PCOLCE2).