The Detection of Messenger RNA for Carcinoembryonic Antigen and Cytokeratin 20 in Peritoneal Washing Fluid in Patients with Advanced Gastric Cancer

Carcinoembryonic Antigen (CEA): Origin, Role in Oncology, and Concentrations in Serum and Peritoneal Fluid

CEA (carcinoembryonic antigen), which belongs to the acidic glycoproteins, is primarily produced during the fetal period. Following this stage, low levels of CEA are considered physiological, while elevated concentrations are associated with a range of both benign and malignant pathologies. The liver plays a key role in CEA metabolism. The most common material used to determine CEA concentrations by various techniques is blood, and measuring CEA in peritoneal fluid holds clinical value. CEA has been found to contribute to carcinogenesis, metastasis, and treatment resistance. Therefore, its serum concentration is widely used in oncology for prognosis, disease monitoring, and recurrence detection, despite its limited sensitivity and specificity, which prevent it from serving as a standalone diagnostic tool. Elevated serum CEA levels are linked to worse outcomes in lung, liver, breast, colorectal, and pancreatic cancers. Imaging and multi-marker panels that include CEA enhance diagnostic accuracy, but its role remains context-dependent and varies by cancer type. CEA levels in peritoneal fluid have been explored as a potential marker for detecting malignancy and predicting recurrence, particularly in gastric, gynecological, and colorectal cancers. Peritoneal fluid CEA has also been proven useful in differentiating the etiology of ascites. While cytology remains the standard for the detection of tumor cells in body fluids, its limited sensitivity provides a strong rationale for incorporating peritoneal fluid CEA measurements as a complementary diagnostic tool, potentially alongside other markers. Additionally, the lack of standardized measurement techniques and cut-off values underlines the methodological challenges that still need to be addressed in future research for both serum and peritoneal CEA levels.

UHPLC-ESI-MS/MS Quantification of Relevant Substrates and Metabolites of the Kynurenine Pathway Present in Serum and Peritoneal Fluid from Gastric Cancer Patients-Method Development and Validation

Metabolites and enzymes involved in the kynurenine pathway (KP) are highly promising targets for cancer treatment, including gastrointestinal tract diseases. Thus, accurate quantification of these compounds in body fluids becomes increasingly important. The aim of this study was the development and validation of the UHPLC-ESI-MS/MS methods for targeted quantification of biologically important KP substrates (tryptophan and nicotinamide) and metabolites(kynurenines) in samples of serum and peritoneal fluid from gastric cancer patients. The serum samples were simply pretreated with trichloroacetic acid to precipitate proteins. The peritoneal fluid was purified by solid-phase extraction before analysis. Validation was carried out for both matrices independently. Analysis of the samples from gastric cancer patients showed different accumulations of tryptophan and its metabolites in different biofluids of the same patient. The protocols will be used for the evaluation of tryptophan and kynurenines in blood and peritoneal fluid to determine correlation with the clinicopathological status of gastric cancer or the disease's prognosis.

Detection of micro-metastases by flow cytometry in lymph nodes from patients with penile cancer

Background

The tumor draining lymph node concept was first described in penile cancer for staging. Immunohistochemistry and histopathology evaluations are routinely used in clinical practice to examine lymph nodes for metastasis. However, these methods are time-consuming with low diagnostic accuracy and micro-metastases might be missed. In this study, we aim to evaluate detection of metastatic cells in draining lymph nodes by flow cytometry.

Methods

To assess the sensitivity of micro-metastasis detection by FACS (Fluorescence-activated cell sorting), HeLa cells were titrated into Peripheral blood mononuclear cells (PBMCs) and expression of pan-cytokeratin AE1/AE3 was analyzed. Single cell suspensions were separately prepared from 10 regional lymph nodes obtained from 5 patients with invasive penile cancer undergoing radical surgery and lymph node dissection. Lymph node dereived cells were examined for cell surface expression of EpCAM, E-cadherin and intracellular expression of pan-cytokeratin AE1/AE3 by FACS.

Results

Ten lymph nodes from 5 penile cancer patients were investigated in a head-to-head comparison between FACS and pathology examination of sections. All metastatic lymph nodes verified by pathology examination were also identified by FACS. Two additional lymph nodes with micro-metastases were diagnosed by FACS only.

Conclusions

FACS analyses of pan-cytokeratin AE1/AE3 stained single cells from tumor draining lymph nodes can be used to detect micro-metastases in patients with penile cancer patients.