The class I MHC antigen processing pathway acting as an internal surveillance mechanism to detect any abnormal or foreign protein synthesized in the cell. Tumor antigens encoded in the endogenous DNA of the tumor cell, or encoded in a DNA plasmid or viral vector vaccine taken up by an APC, are synthesized and cleaved by the 26S proteasome into fragments that are transported by TAP, the transporter associated with antigen processing, into the endoplasmic reticulum, where they are loaded onto newly synthesized class I MHC molecules that transport them to the cell surface for recognition by the T cell receptor.