CA9 and neoplasm: While the transcriptome data were consistent with positive correlation of hypoxia to CA expression, there were also significant differences in our findings between protein and transcriptome level, as mentioned above: While patient tumor samples classified into the CMS1 group showed the highest expression of CA9 and CA12 (together with CMS3) on a transcriptome level, neither our immunohistochemical analysis of spheroid and xenograft tumor tissue nor our analyses in the 2D models showed any abundance of CA expression close to that of the CMS3 group.