Surgical treatment and prognosis is different in esophageal, cardiac and distal gastric
adenocarcinomas. Determination of the origin, in particular of
adenocarcinomas situated at the gastroesophageal junction, may be difficult. It has been suggested that esophageal
adenocarcinomas are characterized by a specific
cytokeratin pattern, namely the CK7+/CK20- pattern. According to the same authors, this
cytokeratin pattern is absent in gastric
adenocarcinomas. The aim of our study is to evaluate if this
cytokeratin pattern CK7+/CK20- is absent in cardiac and distal gastric
adenocarcinomas. Therefore, we evaluated the combined immunohistochemical expression of CK7 and CK20 on
paraffin-embedded material of 214 resection specimens for
adenocarcinoma, comprising 66 esophageal, 73 cardiac and 75 distal gastric
adenocarcinomas (UICC-classification). The
adenocarcinomas were subtyped into intestinal- and diffuse-type according to the Lauren classification. The immunohistochemical staining was considered as positive if 50% or more of the
tumor cells were stained. Statistical analysis has been performed applying the chi2-test. The
tumors situated at the gastroesophageal junction, esophageal as well as cardiac
adenocarcinomas, showed predominantly a CK7+/CK20- expression pattern (67 vs 68%), whereas this
cytokeratin pattern is rather uncommon in distal gastric
adenocarcinomas (31%, P<4 x 10(-5)). Independent of their localization, intestinal- as well as diffuse-type
adenocarcinomas have a similar
cytokeratin pattern. Our data show that the combined expression of CK7 and CK20 is different for the
adenocarcinomas situated on both sides of the gastroesophageal junction compared to the distal gastric
adenocarcinomas. However, in contrast to data in the literature, the combined expression of CK7 and CK20 has a low specificity in the distinction between esophageal and cardiac
adenocarcinomas. This may suggest a similar origin (cell lineage) and thus may have an impact on therapeutic strategies.