Finally, meta-analyses were performed for the prognostic effect of the stem cell markers c-KIT, CD44, CD133, CD24, and NANOG in AdCC and MEC subgroups with advanced or small tumor sizes, AdCC subgroups with or without perineural invasion and metastasis; and in MEC subgroups with high/intermediate or low histopathological grade, without, however, concluding in any statistically significant results (Table S13). This evidence concerns the gene CD44 and neoplasm.