Upper GI biopsies for adenocarcinoma - how many biopsies should endoscopists take?

In our large upper GI cancer centre, many biopsy cases do not contain sufficient material for adequate HER2 assessment. In order to meet the four-biopsy requirement for adequate HER2 assessment in >90% of cases, at least eight biopsies need to be taken, while 10 biopsies would be required for the 5-cancer biopsy threshold.