Table 1.

Various cancer related biomarkers and their expression in various cancers

Biomarkers	Description	Inhibitors	References
EGFR and HER2	EGFR is a protein found in the membrane of several types of cancers. Its mutation is mainly associated with autonomous cell growth, apoptosis inhibition, and metastases. It belongs to tyrosine kinase family i.e. HER family. Binding EGFR as dimers either with itself or HER2 will further stimulate protein-tyrosine kinase and activate the intracellular protein tyrosine kinase	Cetuximab, zalutumumab,matuzumab, pertuzumab	Chen et al. (2013); Sebastian et al. (2006); Casalini et al. (2004)
VEGF receptor (VEGFR)	VEGF belongs to the growth factor family and plays a crucial role in angiogenesis (employed in tumor progression). To inhibit the VEGF-VEGFR interaction one approach is to sequester VEGF with antibody and second is to block VEGFR	Bevacizumab, IMC-1C11, IMC-1121B and CDP791	Ferrara (2002); Youssoufian et al. (2007); Chen et al. (2013)
Folate receptor (FR)	FR has been found to be overexpressed in many cancers mainly ovarian and endometrial cancers. Folic acid binds to cancer cells 20 times more than normal epithelial cells	Farletuzumab, vintafolide	Chen et al. (2013); Weitman et al. (1992); Marchetti et al. (2014); Cheung et al. (2016)
Prostate-specific membrane antigen (PSMA)	PSMA is a transmembrane glycoprotein, expressed moderately in hyperplastic and benign prostates but highly up regulated in malignant tissues. Its increased expression is related to tumor aggressiveness and also found to be overexpressed in non-prostatic tumors like colon, breast, and lung	7E1, J591. MDX-070, BIND-014	Israeli et al. (1993); Olson et al. (2007); Chen et al. (2013)
Phosphatidylserine (PS)	In normal cells, PS flattened on the cytosolic side whereas, in apoptotic cells, it flipped to the outer side. Its high level is found in tumor vascular endothelium	Phosphatidylcholine-stearylamine (PC-SA)	Verhoven et al. (1995); Chen et al. (2013); De et al. (2018)
Integrins	Integrins belong to the family of cell adhesion molecules. Plays crucial role in tumor angiogenesis. Particularly, integrin αvβ3 is widely studied as tumor biomarker and efficiently binds to arginine-glycine-aspartic acid (RGD)	Volociximab, Intetumumab, LM609	Hynes (2002); Kobayashi et al. (2017); Chen et al. (2013)
Matrix metalloproteinase (MMP)	MMP belongs to zinc-dependent endopeptidases family and able to degrade component of extracellular matrix (ECM). Its activation is associated with tumor. MMP2 high expression is found in breast cancer cells	Peptide sequence, HWKHLHNTKTFL, short target peptide, CTTHWGFTLC,	Chen et al. (2013); Scherer et al. (2008)