Immunocytochemical detection of epithelial cells in bone marrow of carcinoma of the upper GI tract: Incidence, clinical significance, and prognostic relevance

In this review, the influence of epithelial cells detected in bone marrow o f patients with carcinoma of the upper GI tract on prognosis is analyzed. M ethodological variables affecting bone marrow sampling, immunocytochemical approaches, and phenotyping of epithelial cells were evaluated as well as t he correlation to clinical factors. The detection of epithelial cells in bo ne marrow varies between 25 and 82% in gastric cancer patients and is about 40% in esophageal cancer patients. Univariate analysis revealed that the i ncidence of epithelial cells in bone marrow is correlated in gastric cancer patients to the Lauren classification, to the lymph node involvement, and to an increased recurrence rate. First results of phenotyping epithelial ce lls showed that uPA receptor expression is correlated with clinical prognos is in gastric cancer patients. The finding of cytokeratin (CK)-positive cel ls in bone marrow of esophageal cancer patients is predictive of a reduced relapse-free and overall survival indicating a hematogenous dissemination o f viable malignant cells leading to an increased risk of metastatic relapse . Preliminary investigations showed that epithelial cells are tumorigenic a nd resistant to neoadjuvant therapy in GI tract cancer. In conclusion, immu nocytologically and phenotyping of CK-positive cells might be helpful for t umor staging and to monitor the response of neoadjuvant therapy, but the re sults should be confirmed in multivariate analysis.