Elevated Level of Serum Carcinoembryonic Antigen (CEA) and Search for a Malignancy: A Case Report

Role of Carcinoembryonic Antigen in Severity Assessment and Mortality Prediction in COVID-19 Patients

Background Early risk stratification of COVID-19 may yield a better prognosis by tailoring effective treatment strategies. Recent studies have identified that elevated carcinoembryonic antigen (CEA) has prognostic value in terms of disease severity and mortality in patients with pneumonia. This study aims to explore the potential of CEA as a marker for both severity assessment and mortality prediction in COVID-19 patients. Methods From August 2020 to October 2021, we conducted this observational study in which patients who tested positive for COVID-19 by reverse transcription polymerase chain reaction (RT-PCR) or had high-resolution computed tomography (HRCT) chest suggestive of COVID-19 were included on day 0 of their admission to the COVID unit. Patients were classified into mild, moderate, severe, and critical according to the World Health Organization (WHO) guidelines. Blood samples were collected for complete blood count (CBC), C-reactive protein (CRP), ferritin, and CEA on days 0, 3, 7, and 14 of admission. The patient's profile was used to obtain lactate dehydrogenase (LDH), D-dimer, and HRCT scores [based on COVID-19 reporting and data system (CO-RADS) grade]. We used receiver operating characteristic (ROC) curves with Youden's index to find the initial (day 0) critical values of CEA for each of mild, moderate, severe, and critical COVID-19. The Kaplan-Meier survival curve was used to predict mortality with the best initial (day 0) cut-off value of CEA. Results Among 75 patients in this study, 15, 20, 19, and 21 were in the mild, moderate, severe, and critical groups, respectively; most were male (68%), and mortality was 18 (24%). Spearman's rank correlation test demonstrates a strong correlation between COVID-19 severity and changes in CEA. In the ROC curves, the area under the curve (AUC) value of CEA was higher among markers in all classifications except for mild to moderate disease. The AUC and critical values of CEA were as follows: for mild to moderate (0.948), 2.5 ng/ml; moderate to severe (1.000), 6.02 ng/ml; and severe to critical (0.769), 11.75 ng/ml. The survival curve shows the best initial cut-off values for mortality outcomes: CEA ≥7.15, CRP ≥81.52, ferritin ≥680.68, lymphocyte percentage ≤7.5, and neutrophil lymphocyte ratio ≥12.7. Conclusions The initial levels of CEA can serve as markers for severity assessment and mortality outcome prediction of COVID-19.

Choosing Wisely Philippines: ten low-value or harmful practices that should be avoided in cancer care

The Choosing Wisely Philippines campaign is an initiative that identifies low-value or potentially harmful practices that are relevant to patients with cancer in the Philippines. The main purpose of these initiatives is to facilitate quality improvement systems and maximise patient outcomes. Of the ten practices identified, four are new recommendations, and six are modified adaptations from previous Choosing Wisely initiatives in the USA and Africa. Recommendations in the final list include interventions involving diagnosis (two practices), treatment (five practices), palliative and supportive care (two practices) and surveillance (1 practice).

Design Strategies for Electrochemical Aptasensors for Cancer Diagnostic Devices

Improved outcomes for many types of cancer achieved during recent years is due, among other factors, to the earlier detection of tumours and the greater availability of screening tests. With this, non-invasive, fast and accurate diagnostic devices for cancer diagnosis strongly improve the quality of healthcare by delivering screening results in the most cost-effective and safe way. Biosensors for cancer diagnostics exploiting aptamers offer several important advantages over traditional antibodies-based assays, such as the in-vitro aptamer production, their inexpensive and easy chemical synthesis and modification, and excellent thermal stability. On the other hand, electrochemical biosensing approaches allow sensitive, accurate and inexpensive way of sensing, due to the rapid detection with lower costs, smaller equipment size and lower power requirements. This review presents an up-to-date assessment of the recent design strategies and analytical performance of the electrochemical aptamer-based biosensors for cancer diagnosis and their future perspectives in cancer diagnostics.

Applications of Graphene Quantum Dots in Biomedical Sensors

Due to the proliferative cancer rates, cardiovascular diseases, neurodegenerative disorders, autoimmune diseases and a plethora of infections across the globe, it is essential to introduce strategies that can rapidly and specifically detect the ultralow concentrations of relevant biomarkers, pathogens, toxins and pharmaceuticals in biological matrices. Considering these pathophysiologies, various research works have become necessary to fabricate biosensors for their early diagnosis and treatment, using nanomaterials like quantum dots (QDs). These nanomaterials effectively ameliorate the sensor performance with respect to their reproducibility, selectivity as well as sensitivity. In particular, graphene quantum dots (GQDs), which are ideally graphene fragments of nanometer size, constitute discrete features such as acting as attractive fluorophores and excellent electro-catalysts owing to their photo-stability, water-solubility, biocompatibility, non-toxicity and lucrativeness that make them favorable candidates for a wide range of novel biomedical applications. Herein, we reviewed about 300 biomedical studies reported over the last five years which entail the state of art as well as some pioneering ideas with respect to the prominent role of GQDs, especially in the development of optical, electrochemical and photoelectrochemical biosensors. Additionally, we outline the ideal properties of GQDs, their eclectic methods of synthesis, and the general principle behind several biosensing techniques.

Graphene Quantum Dot-Based Electrochemical Immunosensors for Biomedical Applications

In the area of biomedicine, research for designing electrochemical sensors has evolved over the past decade, since it is crucial to selectively quantify biomarkers or pathogens in clinical samples for the efficacious diagnosis and/or treatment of various diseases. To fulfil the demand of rapid, specific, economic, and easy detection of such biomolecules in ultralow amounts, numerous nanomaterials have been explored to effectively enhance the sensitivity, selectivity, and reproducibility of immunosensors. Graphene quantum dots (GQDs) have garnered tremendous attention in immunosensor development, owing to their special attributes such as large surface area, excellent biocompatibility, quantum confinement, edge effects, and abundant sites for chemical modification. Besides these distinct features, GQDs acquire peroxidase (POD)-mimicking electro-catalytic activity, and hence, they can replace horseradish peroxidase (HRP)-based systems to conduct facile, quick, and inexpensive label-free immunoassays. The chief motive of this review article is to summarize and focus on the recent advances in GQD-based electrochemical immunosensors for the early and rapid detection of cancer, cardiovascular disorders, and pathogenic diseases. Moreover, the underlying principles of electrochemical immunosensing techniques are also highlighted. These GQD immunosensors are ubiquitous in biomedical diagnosis and conducive for miniaturization, encouraging low-cost disease diagnostics in developing nations using point-of-care testing (POCT) and similar allusive techniques.

An aptasensor for the detection of Mycobacterium tuberculosis secreted immunogenic protein MPT64 in clinical samples towards tuberculosis detection

This work presents experimental results on detection of Mycobacterium tuberculosis secreted protein MPT64 using an interdigitated electrode (IDE) which acts as a platform for capturing an immunogenic protein and an electrochemical impedance spectroscopy (EIS) as a detection technique. The assay involves a special receptor, single stranded DNA (ssDNA) aptamer, which specifically recognizes MPT64 protein. The ssDNA immobilization on IDE was based on a co-adsorbent immobilization at an optimized ratio of a 1/100 HS-(CH₆)₆-OP(O)₂O-(CH₂CH₂O)₆-5′-TTTTT-aptamer-3′/6-mercaptohexanol. The optimal sample incubation time required for a signal generation on an aptamer modified IDE was found to be at a range of 15–20 min. Atomic Force Microscopy (AFM) results confirmed a possible formation of an aptamer - MPT64 complex with a 20 nm roughness on the IDE surface vs. 4.5 nm roughness for the IDE modified with the aptamer only. A limit of detection for the EIS aptasensor based on an IDE for the detection of MPT64 in measurement buffer was 4.1 fM. The developed EIS aptasensor was evaluated on both serum and sputum clinical samples from the same TB (−) and TB (+) patients having a specificity and sensitivity for the sputum sample analysis 100% and 76.47%, respectively, and for the serum sample analysis 100% and 88.24%, respectively. The developed aptasensor presents a sensitive method for the TB diagnosis with the fast detection time.

Development and validation of scFv-conjugated affinity silk protein for specific detection of carcinoembryonic antigen

The production costs for monoclonal antibodies (MAbs) utilized in medical diagnostic kits are inevitably high because the MAbs are mostly obtained from hybridoma cell culture. Here, we report the development and validation of a novel affinity silk protein produced by transgenic silkworm technology as a possible alternative diagnostic tool for cancers. We generated a transgenic silkworm expressing a cDNA construct containing fibroin L-chain fused to a single-chain variable fragment (scFv) derived from a MAb against carcinoembryonic antigen (CEA). The transgenic cocoons were dissolved in aqueous lithium bromide solution, applied to 96-well plates, and analysed by enzyme-linked immunosorbent assay. The scFv-conjugated affinity silk protein specifically recognized CEA as well as the parental MAb. The binding activity was retained after several months of storage in coated plates or concentrated solution. Thus, the scFv-conjugated affinity silk protein provides a potentially useful alternative to conventional MAbs in medical diagnostic kits.

Factors Requiring Adjustment in the Interpretation of Serum Carcinoembryonic Antigen: A Cross-Sectional Study of 18,131 Healthy Nonsmokers

Serum carcinoembryonic antigen (CEA) is a well-known tumor marker for colorectal adenocarcinoma. However, CEA levels can be influenced by various nonmalignant conditions. A retrospective, cross-sectional study was performed including 18,131 healthy nonsmokers who underwent health check-ups with evaluation of the serum CEA level. In the training set, multivariate analysis revealed that the log-transformed CEA level had positive relationships with age (regression coefficient (r) = 0.005, P < 0.001), white blood cell (WBC) count (r = 0.007, P = 0.016), hemoglobin (HB, r = 0.016, P < 0.001), aspartate aminotransferase (AST, r = 0.002, P = 0.005), creatinine (r = 0.076, P = 0.038), and glycosylated hemoglobin (HbA1c, r = 0.052, P < 0.001); body mass index (BMI, r = -0.007, P < 0.001) showed a negative correlation. The results for age, BMI, WBC count, HB, AST, and HbA1c were validated in the test set. We were able to construct the following model to predict the log-transformed CEA level: log (CEA + 0.51) = -0.204 - 0.051 (gender) + 0.005 (age) - 0.006 (BMI) + 0.008 (WBC count) + 0.016 (HB) + 0.002 (AST) + 0.062 (creatinine) + 0.054 (HbA1c). For colorectal cancer prediction, the model with the observed CEA and adjusted CEA levels had significantly high predictive power (AUC 0.756, P < 0.001) than the model only including the observed CEA level (AUC 0.693, P < 0.001). Factors influencing serum CEA levels should be adjusted before clinical interpretation to increase the predictive value of CEA.