Table 1.

Types of antigens explored for tumor vaccine development

Antigen types	Attributes	Reference
Shared antigens	They are observed in different tumors; however, normal tissues express them differently, e.g. antigens like MAGE, NY-ESO-1, etc. are considered shared antigens.	(Raza et al., 2020)
Unique antigens	They are expressed specifically by individual tumors & are expressed by point mutations or splicing alterations; e.g. cancer testis antigen.	(Gordeeva, 2018)
Indispensable antigens	They are necessary for cancer progression and are usually overexpressed by totipotent neoplastic and pluripotent foetal cells, but are rarely seen in normal cells; e.g. HER2, claudin 18.2. Targeting such antigens could be highly beneficial for successful and efficacious vaccine development.	(Barati et al., 2021)
Neoantigens	They are tumor-specific in nature, produced by mutations in tumor cells. High specificity at the cellular level for targeting primary tumor cells as well as circulating tumor cell clusters.	(Duarte & Jill M.Lenardo, 2020)