Cancer stem-like cells (CSCs) possess the ability to self-renew and differentiate, and they are among the major factors driving
tumorigenesis,
metastasis, and resistance to
chemotherapy. Therefore, it is critical to understand the molecular substrates of CSC biology so as to discover novel molecular biosignatures that distinguish CSCs and
tumor cells. Here, we report new findings and insights by employing four transcriptome datasets associated with CSCs, with CSC and
tumor samples from breast, lung, oral, and ovarian tissues. The CSC samples were analyzed to identify differentially expressed genes between CSC and
tumor phenotypes. Through comparative profiling of expression levels in different
cancer types, we identified 17 "seed genes" that showed a mutual differential expression pattern. We showed that these seed genes were strongly associated with
cancer-associated signaling pathways and biological processes, the immune system, and the key
cancer hallmarks. Further, the seed genes presented significant changes in their expression profiles in different
cancer types and diverse mutation rates, and they also demonstrated high potential as diagnostic and prognostic
biomarkers in various
cancers. We report a number of seed genes that represent significant potential as "systems
biomarkers" for understanding the pathobiology of
tumorigenesis. Seed genes offer a new innovation avenue for potential applications toward
cancer precision medicine in a broad range of
cancers in oncology in the future.