Table 3 Important molecular roles and processes of resistance gene expression in mammalian cancer stem cells

ABC Transporters (e.g., ABCB1, ABCG2)

Efflux of chemotherapeutic drugs

Overexpression or altered expression due to genetic mutations, epigenetic modifications (e.g., DNA methylation, histone modifications), or transcriptional regulation by signaling pathways (e.g., Notch, Wnt)

[115, 265, 266]

DNA Repair Genes (e.g., BRCA1, BRCA2, ATM)

Repair of DNA damage caused by chemotherapy or radiation

Overexpression or enhanced activity due to genetic mutations, epigenetic modifications, or transcriptional regulation by signaling pathways (e.g., PI3K/AKT, NF-κB)

[114, 267, 268]

Anti-Apoptotic Genes (e.g., Bcl-2, Bcl-xL)

Inhibition of apoptosis

Overexpression or altered expression due to genetic mutations, epigenetic modifications, or transcriptional regulation by signaling pathways (e.g., PI3K/AKT, NF-κB)

[110, 138, 269]

Stem Cell Markers (e.g., CD44, CD133, ALDH1)

Maintenance of stem cell phenotype and self-renewal

Overexpression or altered expression due to genetic mutations, epigenetic modifications, or transcriptional regulation by signaling pathways (e.g., Notch, Wnt, Hedgehog)

[22, 107, 194, 270,271,272,273]

Epithelial–Mesenchymal Transition (EMT) Markers (e.g., vimentin, N-cadherin, Twist)

Acquisition of migratory and invasive properties

Overexpression or altered expression due to genetic mutations, epigenetic modifications, or transcriptional regulation by signaling pathways (e.g., TGF-β, Wnt, Notch)

[121, 274, 275]

Metabolic Enzymes (e.g., GLUT1, LDHA)

Altered metabolism to support survival and proliferation under stress conditions

Overexpression or altered expression due to genetic mutations, epigenetic modifications, or transcriptional regulation by signaling pathways (e.g., HIF-1α, MYC)

[110, 111, 276]