Diagnostic value of tumor markers in identifying favorable or unfavorable subsets in patients with cancer of unknown primary: a retrospective study.

BACKGROUND: Routine measurement of tumor markers is not recommended in daily clinical practice for patients with cancer of unknown primary (CUP). We evaluated the diagnostic value of tumor markers in identifying favorable or unfavorable subsets in patients with CUP. METHODS: We retrospectively reviewed the medical records of patients who were diagnosed with CUP between October 2010 and July 2015 at the National Cancer Center Hospital. The tumor markers of the patients were examined, including squamous cell carcinoma antigen, cytokeratin fraction, carcinoembryonic antigen, sialyl Lewis X, neuron-specific enolase, pro-gastrin-releasing peptide, α-fetoprotein, protein induced by vitamin K absence or antagonist II, prostate-specific antigen, soluble interleukin-2 receptor, carbohydrate antigen 19-9, cancer antigen 125, cancer antigen 15-3, NCC-ST-439 (ST439), elastase-1, human chorionic gonadotropin, and sialyl-Tn (STN). RESULTS: Among 199 patients with suspected CUP, 90 were diagnosed with confirmed CUP (12 in the favorable subset and 78 in the unfavorable subset). No tumor markers showed 100% sensitivity for unfavorable subsets. ST439 (p = 0.03) and STN (p = 0.049) showed 100% specificity for unfavorable subsets. CONCLUSIONS: For patients with suspected CUP who show elevated ST439 or STN levels, the treatment strategy should be based on the premise that the patient is likely to be placed in the unfavorable subset.

Systematic review and meta-analysis of the clinical survival significance of Sialyl-Tn expression in histological tissues from cancer patients.

BACKGROUND: The expression of Sialyl-Tn (STn) has been associated with different mechanisms of cancer. Several studies using histological tissue samples from different types of cancer showed differences in the STn expression patterns, but few studies have explored the association between STn expression and decreased overall survival. Therefore, a comprehensive analysis of the clinical significance of STn in cancer patients was performed. METHODS: A systematic review and meta-analysis were done of scientific articles published and available from different sources, including MEDLINE/PubMed, Web of Science, Cochrane Library and LILACS. Odds ratio (OR) was represented by the number of deaths during follow-up in positive-STn versus negative-STn patients. OR from each study was pooled and the results were presented in a forest plot. RESULTS: Eleven articles were included in the systematic meta-analysis. The estimated OR of 3.26 (95% CI: 2.12-5.02) was obtained. Furthermore, subgroups studies of gastric cancer showed an OR of 3.74 (95% CI: 2.47-5.66) and other cancer types reported an OR of 2.92 (95% CI: 1.16-7.32). CONCLUSIONS: This study showed that survival time was significantly longer in patients with negative-STn tumors than in those with positive results.

Extended half-life target module for sustainable UniCAR T-cell treatment of STn-expressing cancers.

BACKGROUND: Adapter chimeric antigen receptor (CAR) approaches have emerged has promising strategies to increase clinical safety of CAR T-cell therapy. In the UniCAR system, the safety switch is controlled via a target module (TM) which is characterized by a small-size and short half-life. The rapid clearance of these TMs from the blood allows a quick steering and self-limiting safety switch of UniCAR T-cells by TM dosing. This is mainly important during onset of therapy when tumor burden and the risk for severe side effects are high. For long-term UniCAR therapy, the continuous infusion of TMs may not be an optimal setting for the patients. Thus, in later stages of treatment, single infusions of TMs with an increased half-life might play an important role in long-term surveillance and eradication of residual tumor cells. Given this, we aimed to develop and characterize a novel TM with extended half-life targeting the tumor-associated carbohydrate sialyl-Tn (STn). METHODS: The extended half-life TM is composed of the STn-specific single-chain variable fragment (scFv) and the UniCAR epitope, fused to the hinge region and Fc domain of a human immunoglobulin 4 (IgG4) antibody. Specific binding and functionality of the αSTn-IgG4 TM as well as pharmacokinetic features were assessed using in vitro and in vivo assays and compared to the already established small-sized αSTn TM. RESULTS: The novel αSTn-IgG4 TM efficiently activates and redirects UniCAR T-cells to STn-expressing tumors in a target-specific and TM-dependent manner, thereby promoting the secretion of proinflammatory cytokines and tumor cell lysis in vitro and in experimental mice. Moreover, PET-imaging results demonstrate the specific enrichment of the αSTn-IgG4 TM at the tumor site, while presenting a prolonged serum half-life compared to the short-lived αSTn TM. CONCLUSION: In a clinical setting, the combination of TMs with different formats and pharmacokinetics may represent a promising strategy for retargeting of UniCAR T-cells in a flexible, individualized and safe manner at particular stages of therapy. Furthermore, as these molecules can be used for in vivo imaging, they pose as attractive candidates for theranostic approaches.

The androgen receptor controls expression of the cancer-associated sTn antigen and cell adhesion through induction of ST6GalNAc1 in prostate cancer.

Patterns of glycosylation are important in cancer, but the molecular mechanisms that drive changes are often poorly understood. The androgen receptor drives prostate cancer (PCa) development and progression to lethal metastatic castration-resistant disease. Here we used RNA-Seq coupled with bioinformatic analyses of androgen-receptor (AR) binding sites and clinical PCa expression array data to identify ST6GalNAc1 as a direct and rapidly activated target gene of the AR in PCa cells. ST6GalNAc1 encodes a sialytransferase that catalyses formation of the cancer-associated sialyl-Tn antigen (sTn), which we find is also induced by androgen exposure. Androgens induce expression of a novel splice variant of the ST6GalNAc1 protein in PCa cells. This splice variant encodes a shorter protein isoform that is still fully functional as a sialyltransferase and able to induce expression of the sTn-antigen. Surprisingly, given its high expression in tumours, stable expression of ST6GalNAc1 in PCa cells reduced formation of stable tumours in mice, reduced cell adhesion and induced a switch towards a more mesenchymal-like cell phenotype in vitro. ST6GalNAc1 has a dynamic expression pattern in clinical datasets, beingsignificantly up-regulated in primary prostate carcinoma but relatively down-regulated in established metastatic tissue. ST6GalNAc1 is frequently upregulated concurrently with another important glycosylation enzyme GCNT1 previously associated with prostate cancer progression and implicated in Sialyl Lewis X antigen synthesis. Together our data establishes an androgen-dependent mechanism for sTn antigen expression in PCa, and are consistent with a general role for the androgen receptor in driving important coordinate changes to the glycoproteome during PCa progression.