Fig. 6: A typical case of gastric MANEC displayed loss of MAPK1 only in the NEC component.

a The loss of 22q11.21 (including MAPK1, black arrow) was much more significant in the NEC component than in the ADC component in the whole genome view. b FISH analysis showed loss of the MAPK1 gene (one orange signal) in the NEC component and diploid signals (pairs of orange signals) in the ADC component. c qPCR validation of MAPK1 in 18 gastric MANECs. The CN of MAPK1 was significantly lower in the NEC component than in the ADC component and normal tissue. d Immunohistochemistry staining (200×) showed the negative expression of ERK2 (the protein product of MAPK1) in the NEC component and the positive expression of ERK2 in the ADC component and normal mucosa.