Pre- and Postoperative Levels of Carcinoembryonic Antigen in Microsatellite Stable Versus Instable Colon Cancer: a Retrospective Analysis.

PURPOSE: The prognosis of microsatellite stable (MSS) versus instable (MSI) tumors is an ongoing matter of debate, with differences in expression of carcinoembryonic antigen (CEA) in these two tumor subsets being inconsistently reported to date. The aim of this study was to investigate CEA expression in the context of clinical parameters in MSS and MSI tumors. METHODS: Clinical, pathological, and biochemical parameters of colon cancer patients who underwent curative surgery were documented in a database and compared between MSS and MSI cases. The pre- to postoperative trend of CEA was analyzed. Survival was assessed using the Kaplan-Meier (log rank) test. RESULTS: One hundred sixty-nine patients were included in the study. Compared to those with MSS tumors, there was a higher proportion of preoperatively elevated CEA among those with MSI tumors (p = 0.067). Median CEA values decreased over the pre- to postoperative course with MSS (p = 0.01) but not MSI (p = 0.093) tumors. The distribution of N classification differed between MSS and MSI tumors (p = 0.014). Patients with MSI tumors had superior survival. CONCLUSION: Despite the better prognosis, MSI tumors are associated with increases in CEA. Our findings shed light on discrepancies related to the prognostic evaluation of MSI tumors. Furthermore, in follow-up of colorectal cancers, CEA measurements should be interpreted differently for MSI and MSS tumors.

Are morphological criteria sufficient for the identification of circulating tumor cells in renal cancer?

BACKGROUND: Single circulating tumor cells (CTCs) or circulating tumor microemboli (CTMs) are potential biomarkers of renal cell cancer (RCC), however studies of CTCs/CTMs in RCC are limited. In this pilot study we aimed to evaluate a novel blood filtration technique suited for cytomorphological classification, immunocytochemical and molecular characterization of filtered, so called circulating non-hematologic cells (CNHCs) - putative CTCs/CTMs - in patients with RCC. METHODS: Blood of 40 patients with renal tumors was subjected to ScreenCell filtration. CNHCs were classified according to cytomorphological criteria. Immunocytochemical analysis was performed with antibodies against CD45, CD31 and carbonic anhydrase IX (CAIX, a RCC marker). DNA of selected CNHCs and respective primary tumors was analysed by array-CGH. RESULTS: CNHC-clusters with malignant or uncertain malignant cytomorphological features - putative CTMs - were negative for CD45, positive for CD31, while only 6% were CAIX positive. Array-CGH revealed that 83% of malignant and uncertain malignant cells did represent with a balanced genome whereas 17% presented genomic DNA imbalances which did not match the aberrations of the primary tumors. Putative single CTCs were negative for CD45, 33% were positive for CD31 and 56% were positive for CAIX. CONCLUSIONS: The majority of CNHC-clusters, putative CTMs, retrieved by ScreenCell filtration may be of endothelial origin. Morphological criteria seem to be insufficient to distinguish malignant from non-malignant cells in renal cancer.