Table 2.

Functions of galectins in different tumors

Galectin (Gal)	Cancer type	Effect	Mechanisms	Refs
Gal-1	Glioma, breast, ovarian, cervical, pancreas, prostate, thyroid, colorectal, lung, melanoma, neuroblastoma, hepatic, gastric, bladder	Increases cell growth, migration, invasion, angiogenesis, metastasis and chemotherapy resistance, induces tumor immune evasion, promotes tumor progression, inhibits apoptosis	Interacts with glycoconjugates and regulates the biological activities of H-Ras/MEK/ERK, β-catenin pathways in the tumor microenvironment	[16, 24–29]
Gal-3	Glioma, breast, ovarian, cervical, pancreas, prostate, thyroid, colorectal, liver, lung, melanoma, neuroblastoma, bladder, gastric, tongue, renal	Increases metastasis formation, reduces apoptosis and induces tumor immune evasion, increase adhesion, tumor growth and motility, induces chemoresistance, cell proliferation, angiogenesis and migration, regulate cell cycle and cell transformation	Regulates M2 polarization of macrophages and triggers apoptosis via its binding to antitumor T cells. Induces the expression of matrix metalloproteinases through p38-MAPK pathway. Maintains mitochondrial homeostasis and regulates tumor metabolism	[17, 30–45]
Gal-8	Glioma, breast, ovarian, prostate, thyroid, colon, liver, lung, bladder, renal, laryngeal	Mediates cell adhesion, migration, proliferation and survival	Binds to integrins and activates the downstream FAK pathway, interacts with activated leukocyte cell adhesion molecule receptors	[46–57]
Gal-9	Glioma, breast, ovarian, cervical, pancreas, prostate, colon, liver, lung, melanoma, renal, oral, myeloma, cholangiocarcinoma, esophageal	Affects cell adhesion and metastasis, induces apoptosis	Regulates JNK and p38 MAP kinase pathways, mitochondrial pathway, blocks adhesion to endothelium and extracellular matrices	[58–68]
Gal-4	Glioma, breast, ovarian, cervical, pancreas, colorectal, liver, lung	Promotes adhesion, reduces cell migration and metastasis formation, induces cell cycle arrest	Interacts with and down-regulates the functions of Wnt signaling pathway. Interferes with the integrin beta 4/Src/FAK cascade	[69–76]
Gal-7	Breast, ovarian, colon, cervical, neuroblastoma, melanoma, gastric, urothelial, thyroid	Correlates with cell proliferation, migration, infiltration and chemosensitivity	Inhibits the TGF beta/Smad3 pathway	[77–80]
Gal-2	Breast, colon	Increases adhesion	Unclear	[81, 82]
Gal-12	Cervical, colorectal	Reduces cell growth	Binds to SLC1A5 and inhibits glutamine anaplerosis	[83]