Table 1.
Potential markers of cancer cell invasion.
| Markers | Functions | Expression at the Invasive Front | Limitations | |
|---|---|---|---|---|
| ECM components | Laminin-5, γ2 chain | ECM components, triggering MMP production through interaction with integrins | Breast, pancreatic, colon, lung, and other cancers [46,51,52,55,56] | Expression not only in the invasive front, but in other regions of the tumor [43,46,57,58,59] |
| Fibronectin | Oral and head and neck cancers [60,61] | |||
| Tenascin C | Modulation of cell adhesion | Melanoma, breast, lung, liver, and gallbladder cancers [57,62] | ||
| EMT molecules | Snail, Twist, vimentin | EMT induction and regulation | Various cancers [63] | Snail and Twist: Unstable molecules [64,65], total expression in breast tumors [66]. Vimentin may not be expressed in invasive carcinomas [67] |
| Cell–cell and cell–ECM interaction molecules | Cadherin-catenin complex | Adherens junctions | Colorectal, oral, and basaloid carcinomas (loss of E-cadherin and nuclear localization of β-catenin) [68,69,70,71] | In some tumors, loss of E-cadherin is not indispensable for invasive growth [72] |
| Integrins | Cell–ECM adhesion, involvement in MMP production | Melanoma (αvβ3), colon (αvβ6), head and neck (αvβ6), and lung (α6β4) cancers [73,74,75,76] | Involvement in other biological processes [77,78] | |
| Galectin 1 | Modulation of cell–cell and cell–ECM interactions | Oral and lung cancers, glioblastoma [47,79,80] | ||
| L1CAM | Cell adhesion | Colorectal and pancreatic cancers [81,82] | Dualistic role in cancer progression [83] | |
| Serine proteases and MMPs | uPA | Proteolysis of plasminogen to plasmin | Oral and skin carcinomas [84,85] | Involvement in other biological processes [86,87] |
| MMPs | ECM proteolysis | Melanoma (MMP-2), colorectal (MMP-7), gastric (MMP-7), endometrial (MMP-2, 9), ovarian (MMP-2, 9), and head and neck (MMP-2, 9) cancers [56,88,89,90,91,92,93,94] | ||
| Actin cytoskeleton proteins | Ezrin | Actin polymerization, cytoskeletal dynamics | Lung cancer [95,96] | Involvement in other biological processes. Contradictory data on the role in cancer progression [96] |
| WAVE2 | Breast cancer [97] | - | ||
| Cortactin | Oral and laryngeal cancers [98,99] | - | ||
| MENAinv | Breast cancer [100] | - | ||
| Fascin-1 | Liver, colon, cervical, and endometrial cancers [101,102,103,104] | - | ||
| Other proteins | Ki-67 | Cell proliferation | Breast, oral, and endometrial cancers [6,105,106,107] | Contradictory data on the level of Ki-67 expression at the invasive front [56,69,108] |
| FGFR2 | Cell division, growth and differentiation | Colorectal and cervical cancers [109,110] | Involvement in other biological processes [111] | |
ECM, extracellular matrix; EMT, epithelial–mesenchymal transition; MMPs, matrix metalloproteinases.