Cytokeratin 7/20 and mucin expression patterns in oesophageal, cardia and distal gastric adenocarcinomas

Aims: The current study examined cytokeratin (CK)7 and 20 as well as MUC1–6 immunoprofiles in oesophageal, gastric and gastro–oesophageal junction (GOJ) adenocarcinomas. The aim was to compare expression patterns in these locations as aids to accurate classification of these morphologically similar carcinomas which all may involve the GOJ. Methods and results: Tissue microarrays were constructed using tissue from 14 oesophageal, 78 gastric and 39 GOJ adenocarcinomas. Sections were immunostained with CK7, CK20, MUC1, MUC2, MUC5AC and MUC6. The results of this study showed no differences in CK7 and CK20 expression patterns in the three locations. MUC2 expression was higher proximally (43% of oesophageal, 28% of GOJ and 17% of gastric carcinomas) and MUC6 expression was higher distally (7% of oesophageal, 28% of GOJ and 15% of gastric carcinomas). MUC1 expression was associated with higher pTNM‐stage. Conclusions: CK 7/20 profiles have no role in distinguishing tumours of the three locations. Mucin expression patterns differed in oesophageal and gastric adenocarcinomas, although not sufficiently to classify individual cases. GOJ adenocarcinomas showed a mucin expression pattern that was partly ‘gastric’, and partly ‘oesophageal’. MUC1 expression was associated with a higher pTNM stage.