Analytical interference in CA 19-9 immunoassay generates false-positive results in a young woman with a low-grade appendiceal tumor: An educational case report and brief literature review.

CA 19-9 (carbohydrate antigen 19-9) is a tumor marker widely used for the follow-up of patients with pancreatic cancer and other digestive neoplasia. This case report describes a discrepancy between the results of serum CA 19-9 analyses using the Alinity analytical platform (Abbott™) and two other techniques, Kryptor Gold (ThermoFisher Scientific™) and Cobas E411 (Roche™), in the context of a young woman with appendiceal mucocele. In this context, when the serum concentration of CA 19-9 is high, it may raise concerns about potential malignancy or rupture of the mucocele that may lead to tumoral dissemination in the abdominal cavity. In the present case, we observed with Alinity a false elevation in CA 19-9 concentration at 190 kU/L (normal range < 37 kU/L) before appendix resection that continued to increase until reaching 619 kU/L six months after surgery. This situation led to unnecessary additional tests, increased hospitalization time and stress for the patient who also had to interrupt her medically assisted reproduction project. We solved this case using new measurements in CA 19-9 concentration with two other techniques, Kryptor Gold and Cobas E411, and we identified an analytical interference caused by the presence of heterophile antibodies. In all cases, abnormal result initially obtained with Alinity was found below normal range not only with the two other techniques but also with Alinity after a neutralisation step by using Heterophile Blocking Tubes (Scantibodies Laboratory™). Analytical interferences in medical tests can lead to inappropriate medical care. It is an important issue requiring a continuing training of biologists who must be aware of these problems, which are recurring concerns and are not always easy to identify in laboratories of medical biology, in particular when immunoassays are used. This case report also provides an opportunity to do a brief review of the literature and to remind some recommendations and actions to take into consideration in the presence of discrepancies between the clinic and the biology, in particular, one of them is to measure the biological analyte with a different technique. Moreover, the use of Heterophile Blocking Tubes neutralizing specifically the heterophile antibodies may be useful. In all cases, dialogue between clinicians and biologists remains essential.

Osteopontin (OPN/SPP1), a Mediator of Tumor Progression, Is Regulated by the Mesenchymal Transcription Factor Slug/SNAI2 in Colorectal Cancer (CRC).

In colorectal cancer (CRC), disease-related death is closely linked to tumor aggressiveness and metastasis. Gene expression profiling of patient tumors has suggested that a more mesenchymal phenotype, present in about one-fourth of all patients, is associated with increased aggressiveness. Accordingly, the mesenchymal transcription factor Slug/SNAI2 has been associated with decreased disease-free survival. To decipher the basis for the Slug-mediated phenotype, we conducted RNAseq experiments with a panel of HT-29 CRC cells expressing different levels of Slug, both in vitro and in tumor models. The results show that osteopontin, a secreted pleotropic protein involved in multiple steps of colorectal cancer progression, was highly upregulated by Slug in vitro, as well as in vivo. We further show that Slug is a direct regulator of osteopontin at the promoter level. The levels of secreted osteopontin were correlated with Slug expression, thereby linking the tumor phenotype to a biomarker available by liquid biopsies. The results also suggest that osteopontin neutralization may attenuate at least some of the Slug-mediated functions.

Osteopontin as a Regulator of Colorectal Cancer Progression and Its Clinical Applications.

A high expression of the phosphoprotein osteopontin (OPN) has been associated with cancer progression in several tumor types, including breast cancer, hepatocarcinoma, ovarian cancer, and colorectal cancer (CRC). Interestingly, OPN is overexpressed in CRC and is associated with a poor prognosis linked to invasion and metastasis. Here, we review the regulation and functions of OPN with an emphasis on CRC. We examine how epigenetic and genetic regulators interact with the key signaling pathways involved in this disease. Then, we describe the role of OPN in cancer progression, including proliferation, survival, migration, invasion, and angiogenesis. Furthermore, we outline the interest of using OPN as a clinical biomarker, and discuss if and how osteopontin can be implemented as a routine assay in clinical laboratories for monitoring CRC patients. Finally, we discuss the use of OPN an attractive, but challenging, therapeutic target.

Clinical implications of CTNNA1 germline mutations in asymptomatic carriers.

In 2017, we implemented CTNNA1 germline analysis in probands suspected of having hereditary diffuse gastric cancer. Here, we report the results from a retrospective series of 41 cases, including the identification of a new family with a CTNNA1 mutation and the first prophylactic total gastrectomy in an asymptomatic carrier after a normal upper endoscopy. Diffuse gastric cancer foci with loss of catenin alpha-1 expression were seen in the resected tissue, suggesting that CTNNA1 and CDH1 germline mutations behave in a similar manner. Life-changing prophylactic total gastrectomy should therefore also be considered in CTNNA1 mutation carriers.

Transient increase of CA 19-9 serum concentrations in a liver transplant recipient with cystic fibrosis and hepatic abscess: a case report and brief literature review.

CA 19-9 (carbohydrate antigen 19-9) is a tumor marker widely used for surveillance of patients with pancreatic cancer. However, even high levels of CA 19-9 may not necessarily be cancer-associated thereby complicating the diagnosis. This case report highlights a transient increase of CA 19-9 in a triple transplanted patient with cystic fibrosis and continuous immunosuppression for 20 years who was under antibiotics. This case emphasizes the need for a balanced interpretation of biological results, especially in cases where many confounding factors are present such as diabetes, chronic renal failure, cystic fibrosis and infections. This case also provides an opportunity to formulate a number of recommendations for the interpretation of tumor marker results in order to avoid long and costly further investigations.

Mutant human embryonic stem cells reveal neurite and synapse formation defects in type 1 myotonic dystrophy.

Myotonic dystrophy type 1 (DM1) is a multisystem disorder affecting a variety of organs, including the central nervous system. By using neuronal progeny derived from human embryonic stem cells carrying the causal DM1 mutation, we have identified an early developmental defect in genes involved in neurite formation and the establishment of neuromuscular connections. Differential gene expression profiling and quantitative RT-PCR revealed decreased expression of two members of the SLITRK family in DM1 neural cells and in DM1 brain biopsies. In addition, DM1 motoneuron/muscle cell cocultures showed alterations that are consistent with the known role of SLITRK genes in neurite outgrowth, neuritogenesis, and synaptogenesis. Rescue and knockdown experiments suggested that the functional defects can be directly attributed to SLITRK misexpression. These neuropathological mechanisms may be clinically significant for the functional changes in neuromuscular connections associated with DM1.