Diagnostic potential of nanoparticle aided assays for MUC16 and MUC1 glycovariants in ovarian cancer.

Our study reports the discovery and evaluation of nanoparticle aided sensitive assays for glycovariants of MUC16 and MUC1 in a unique collection of paired ovarian cyst fluids and serum samples obtained at or prior to surgery for ovarian carcinoma suspicion. Selected glycovariants and the immunoassays for CA125, CA15-3 and HE4 were compared and validated in 347 cyst fluid and serum samples. Whereas CA125 and CA15-3 performed poorly in cyst fluid to separate carcinoma and controls, four glycovariants including MUC16MGL , MUC16STn , MUC1STn and MUC1Tn provided highly improved separations. In serum, the two STn glycovariants outperformed conventional CA125, CA15-3 and HE4 assays in all subcategories analyzed with main benefits obtained at high specificities and at postmenopausal and early-stage disease. Serum MUC16STn performed best at high specificity (90%-99%), but sensitivity was also improved by the other glycovariants and CA15-3. The highly improved specificity, excellent analytical sensitivity and robustness of the nanoparticle assisted glycovariant assays carry great promise for improved identification and early detection of ovarian carcinoma in routine differential diagnostics.

Exploratory Analysis of CA125-MGL and -STn Glycoforms in the Differential Diagnostics of Pelvic Masses.

BACKGROUND: The cancer antigen 125 (CA125) immunoassay (IA) does not distinguish epithelial ovarian cancer (EOC) from benign disease with the sensitivity needed in clinical practice. In recent studies, glycoforms of CA125 have shown potential as biomarkers in EOC. Here, we assessed the diagnostic abilities of two recently developed CA125 glycoform assays for patients with a pelvic mass. Detailed analysis was further conducted for postmenopausal patients with marginally elevated conventionally measured CA125 levels, as this subgroup presents a diagnostic challenge in the clinical setting. METHODS: Our study population contained 549 patients diagnosed with EOC, benign ovarian tumors, and endometriosis. Of these, 288 patients were postmenopausal, and 98 of them presented with marginally elevated serum levels of conventionally measured CA125 at diagnosis. Preoperative serum levels of conventionally measured CA125 and its glycoforms (CA125-MGL and CA125-STn) were determined. RESULTS: The CA125-STn assay identified EOC significantly better than the conventional CA125-IA in postmenopausal patients (85% vs. 74% sensitivity at a fixed specificity of 90%, P = 0.0009). Further, both glycoform assays had superior AUCs compared to the conventional CA125-IA in postmenopausal patients with marginally elevated CA125. Importantly, the glycoform assays reduced the false positive rate of the conventional CA125-IA. CONCLUSIONS: The results indicate that the CA125 glycoform assays markedly improve the performance of the conventional CA125-IA in the differential diagnosis of pelvic masses. This result is especially valuable when CA125 is marginally elevated.

A longitudinal analysis of CA125 glycoforms in the monitoring and follow up of high grade serous ovarian cancer.

OBJECTIVE: Cancer antigen 125 (CA125) is generally considered the gold standard of biomarkers in the diagnosis and monitoring of high grade serous ovarian carcinoma (HGSC). We recently reported, that two CA125 glycoforms (CA125-STn and CA125-MGL) have a high specificity to HGSC and further hypothesized, that these cancer specific glycoforms are feasible candidates as biomarkers in HGSC treatment and follow up. METHODS: Our cohort consisted of 122 patients diagnosed with HGSC. Serum samples were collected longitudinally at the time of diagnosis, during treatment and follow up. Serum levels of CA125, CA125-STn and CA125-MGL were determined and compared or correlated with different end points (tumor load assessed intraoperatively, residual disease, treatment response, progression free survival). RESULTS: Serum CA125-STn levels at diagnosis differentiated patients with low tumor load and high tumor load (p = 0,030), indicating a favorable detection of tumor volume. Similarly, the CA125-STn levels at diagnosis were significantly lower in patients with subsequent complete cytoreduction than in patients with suboptimal cytoreduction (p = 0,025). Conventional CA125 did not differentiate these patients (p = 0,363 and p = 0,154). The CA125-STn nadir value predicted the progression free survival of patients. The detection of disease relapse was improved with CA125-STn, which presented higher fold increase in 80,0% of patients and earlier increase in 37,0% of patients. CONCLUSIONS: CA125-STn showed promise as a useful biomarker in the monitoring and follow up of patients with HGSC utilizing a robust and affordable technique. Our findings are topical as a suitable indicator of tumor load facilitates patient selection in an era of new targeted therapies.

Europium Nanoparticle-Based Sialyl-Tn Monoclonal Antibody Discriminates Epithelial Ovarian Cancer-Associated CA125 from Benign Sources.

BACKGROUND: The Sialyl-Thomsen-nouveau antigen (STn) is abundantly produced on many types of human epithelial cancers including epithelial ovarian cancer (EOC). We previously developed an EOC-specific lectin sandwich immunoassay (CA125MGL) using a human macrophage galactose-binding lectin coated on fluorescent europium nanoparticles (Eu+3-NPs) as a tracer and an anti-CA125-specific mAb for capture. Here we have identified a novel STn-mAb that efficiently recognizes the EOC-associated STn antigen on CA125 when coated on Eu+3-NPs. METHOD: CA125 from the ovarian cancer cell line OVCAR-3, placental homogenate, and ascites fluid from patients with liver cirrhosis was captured by anti-CA125 antibody immobilized on microtitration wells and traced with anti-STn-mAb-Eu+3-NPs. Samples from EOC or patients with endometriosis with marginally increased conventional CA125 immunoassay (CA125IA; 35-200 U/mL) and healthy controls were analyzed. RESULTS: An analytically sensitive CA125STn assay that specifically recognized the CA125 isoform produced by OVCAR-3 was achieved. Serum CA125STn concentration was significantly higher in EOC patients than in those with endometriosis (P < 0.001). Furthermore, the sensitivity for detection of EOC with CA125STn assay was 73.3% when 95% of endometriosis cases were undetectable. CONCLUSION: Our findings suggest that Eu+3-NPs-based CA125STn assay could help reduce the false-positive rates of CA125IA to improve differential diagnosis. The results encourage studying further the potential use of CA125STn to detect EOC at earlier clinical stages. This approach warrants further investigation in other cancers as well.