Autoantibodies to mesothelin in infertility

Systematic review: Tumor-associated antigen autoantibodies and ovarian cancer early detection

OBJECTIVES

Tumor-associated autoantibodies (AAbs), produced as an immune response to tumor-associated antigens (TAAs), are a novel pathway of early detection markers.

METHODS

We conducted a systematic review on AAbs and ovarian cancer to summarize the diagnostic performance of individual AAbs and AAb panels. A total of 29 studies including 85 AAbs were included; 27 of the studies were conducted in prevalent cases and cancer-free controls and 2 investigations included pre-diagnosis samples. The majority of studies were hypothesis-driven, evaluating AAbs to target TAAs; 10 studies used screening approaches such as serological expression cloning (SEREX) and nucleic acid-programmable protein arrays (NAPPA).

RESULTS

The highest sensitivities for individual AAbs were reported for RhoGDI-AAbs (89.5%) and TUBA1C-AAbs (89%); however, specificity levels were relatively low (80% and 75%, respectively). High sensitivities at high specificities were reported for HOXA7-AAbs for detection of moderately differentiated ovarian tumors (66.7% sensitivity at 100% specificity) and IL8-AAbs in stage I-II ovarian cancer (65.5% sensitivity at 98% specificity). A panel of 11 AAbs (ICAM3, CTAG2, p53, STYXL1, PVR, POMC, NUDT11, TRIM39, UHMK1, KSR1, and NXF3) provided 45% sensitivity at 98% specificity for serous ovarian cancer, when at least 2 AAbs were above a threshold of 95% specificity. Twelve of the AAbs identified in this review were investigated in more than one study. Data on diagnostic discrimination by tumor histology and stage at diagnosis are sparse. Limited data suggest select AAb markers improve diagnostic discrimination when combined with markers such as CA125 and HE4.

CONCLUSIONS

AAbs for ovarian cancer early detection is an emerging area, and large-scale, prospective investigations considering histology and stage are required for discovery and validation. However, data to date suggests panels of AAbs may eventually reach sufficient diagnostic discrimination to allow earlier detection of disease as a complement to existing markers and transvaginal ultrasound.

Selenium-Binding Protein 1 (SBP1) autoantibodies in ovarian disorders and ovarian cancer

Infertility is a risk factor for ovarian cancer (OvCa). The goal was to determine if antibodies to selenium-binding protein 1 (SBP1), an autoantibody we identified in patients with premature ovarian failure (POF), occurs in both infertility and OvCa patients, and thus could be associated with preneoplasia. Anti-SBP1 was measured by immunoassay against recombinant SBP1, in sera from OvCa (n = 41), infertility (n = 92) and control (n = 87) patients. Infertility causes were POF, unexplained, irregular ovulation or endometriosis. The percent of anti-SBP1-positive sera was higher in POF (P = 0.02), irregular ovulation (P = 0.001), unexplained causes (P = 0.02), late (III-IV)-stage OvCa (P = 0.02) but was not significant in endometriosis, benign ovarian tumors/cysts, early stage (I-II) OvCa or uterine cancer compared to healthy controls. Anti-SBP1 was significantly higher in women with serous (P = 0.04) but not non-serous (P = 0.33) OvCa compared to controls. Also, we determined if anti-SBP1 was associated with CA125 or anti-TP53, markers often studied in OvCa. Anti-TP53 and CA125 were measured by established immunoassays. The ability of anti-SBP1 alone to discriminate infertility or OvCa from controls or when combined with anti-TP53 and CA125, to identify OvCa was evaluated by comparing the area under the curve (AUC) in ROC analysis. Anti-SBP1 alone discriminated infertility (AUC = 0.7; P = 0.001) or OvCa (AUC = 0.67; P = 0.03) from controls. The sensitivity and specificity of OvCa identification was increased by combining CA125, anti-TP53 and anti-SBP1 (AUC = 0.96). Therefore, anti-SBP1 occurs in infertile women with POF, ovulatory disturbances or unexplained infertility and in serous OvCa. This suggests an autoimmune process is associated with the development of serous OvCa.

Anti-HE4 antibodies in infertile women and women with ovarian cancer

OBJECTIVES

To develop an assay for anti-HE4 antibodies and assess such antibodies in sera from women with increased epidemiologic risk for ovarian cancer (infertility) and patients with ovarian cancer in comparison to controls.

METHODS

An ELISA was developed to measure antibodies to recombinant full length HE4 and cut-off values were determined for different levels of specificity (up to 99%).

RESULTS

Infertile women more frequently had anti-HE4 antibodies than controls (23% at 98% specificity, p < 0.001) with antibodies most frequent in women with POF (31%) and ovulatory dysfunction (47%). There was also an increased frequency of anti-HE4 antibodies in patients with ovarian cancer (14% at 97% specificity, p < 0.01), but more women with certain types of infertility have anti-HE4 antibodies than women with ovarian cancer. Most patients with ovarian cancer have circulating HE4 antigen, which may interfere with detection of antibodies, while the level of HE4 antigen in sera from infertile women was not higher than in normal controls. There was a statistically significant correlation between antibodies to HE4 and antibodies to mesothelin in the same patients.

CONCLUSIONS

Women with certain types of infertility, which have increased risk to develop ovarian cancer, and women with ovarian cancer more frequently than controls have antibodies to HE4, a biomarker for ovarian cancer. The antibodies may reflect a tumor-promoting Th2 type of inflammation.

Advances in membrane proteomics and cancer biomarker discovery: current status and future perspective

Membrane proteomic analysis has been proven to be a promising tool for identifying new and specific biomarkers that can be used for prognosis and monitoring of various cancers. Membrane proteins are of great interest particularly those with functional domains exposed to the extracellular environment. Integral membrane proteins represent about one-third of the proteins encoded by the human genome and assume a variety of key biological functions, such as cell-to-cell communication, receptor-mediated signal transduction, selective transport, and pharmacological actions. More than two-thirds of membrane proteins are drug targets, highlighting their immensely important pharmaceutical significance. Most plasma membrane proteins and proteins from other cellular membranes have several PTMs; for example, glycosylation, phosphorylation, and nitrosylation, and moreover, PTMs of proteins are known to play a key role in tumor biology. These modifications often cause change in stoichiometry and microheterogeneity in a protein molecule, which is apparent during electrophoretic separation. Furthermore, the analysis of glyco- and phosphoproteome of cell membrane presents a number of challenges mainly due to their low abundance, their large dynamic range, and the inherent hydrophobicity of membrane proteins. Under pathological conditions, PTMs, such as phosphorylation and glycosylation are frequently altered and have been recognized as a potential source for disease biomarkers. Thus, their accurate differential expression analysis, along with differential PTM analysis is of paramount importance. Here we summarize the current status of membrane-based biomarkers in various cancers, and future perspective of membrane biomarker research.

Evaluation of gastrointestinal symptoms in different patient groups using the visual analogue scale for irritable bowel syndrome (VAS-IBS)

BACKGROUND

Irritable bowel syndrome (IBS) and gastrointestinal (GI) dysmotility disorders have a similar clinical picture, although dysmotility disorders require the attention of a specialist. Patients with primary Sjögren's syndrome (pSS) have also been described to suffer from IBS-like symptoms. No objective marker is available to distinguish between the patients. A visual analogue scale has been developed for IBS patients (VAS-IBS) to measure treatment response of GI symptoms and well-being in patients with IBS. The aim of the present study was to examine if VAS-IBS could be used to compare the degree of GI complaints in different patient populations, to get an objective marker to differentiate between the patients.

METHODS

The VAS-IBS consists of 7 VAS scales, namely, abdominal pain, diarrhoea, constipation, bloating and flatulence, vomiting and nausea, psychological well-being and the intestinal symptoms' influence on daily life. Consecutive female patients suffering from IBS, dysmotility disorders and pSS were asked to complete the VAS-IBS questionnaire when visiting the out-patient clinics. In addition, a control population consisting of healthy female volunteers was included.

RESULTS

Healthy volunteers had almost no GI symptoms, whereas all 3 patient groups expressed symptoms. There was no statistical significant difference between IBS and dysmotility in any of the scales besides vomiting and nausea (p = 0.044). Except for constipation, patients with pSS had less severe symptoms than the others.

CONCLUSION

The VAS-IBS questionnaire could be used to assess the level of GI symptoms. However, VAS scores do not help the clinicians to differentiate between IBS and other dysmotility disturbances.