Immunogen sequence: VDEQPLENYL DMEYFGTIGI GTPAQDFTVV FDTGSSNLWV PSVYCSSLAC TNHNRFNPED SSTYQSTSET VSITYGTGSM TGILGYDTVQ VGGISDTNQI FGLSETEPGS FLYYAPFD; Positive Samples: U-87MG, HT-29, 293T, Mouse brain, Mouse stomach, Rat brain. PGA5: Pepsinogen 5, group