Relationship between circulating tumor-associated autoantibodies and clinical outcomes in advanced-stage NSCLC patients receiving PD-1/-L1 directed immune checkpoint inhibition

BACKGROUND

Durable tumor regressions are observed in a subset of advanced-stage non-small cell lung cancer (NSCLC) patients receiving PD-1/-L1 targeted immune checkpoint inhibitors (or 'immunotherapy') alone or in combination with chemotherapy. However, the majority of advanced NSCLC patients receiving these agents do not experience long-term disease control. Existing methods to identify patients most likely to gain clinical benefit from PD-1/-L1 immunotherapy have limitations, creating a need for improved methods to guide treatment selection, particularly for those likely to benefit from single-agent immunotherapy. Here, we describe the development of a series of novel assays for tumor-associated autoantibodies as part of an exploratory study intended to determine if these biomarkers have potential prognostic value in this setting.

METHOD

A selection of recombinant tumor autoantigens previously characterized for their diagnostic utility were developed and preliminarily evaluated by this study. These include: Fumarate Dehydrogenase (FH), Hydroxysteroid 17-Beta Dehydrogenase 10 (HSD17B10), Inosine Monophosphate Dehydrogenase 2 (IMPDH2), New York Esophageal Squamous Cell Carcinoma-1 (NY ESO-1), Phosphoglycerate Mutase 1 (PGAM1), and Vimentin. Custom Luminex immunobead assays were developed for these targets to quantitatively assess autoantibody levels in individual patient sera. Assays were erected as indirect immunoassays on MagPlex® Microspheres using standard carbodiimide/NHS-based chemistries, utilizing a biotin-conjugated secondary (i.e. anti-human IgG) antibody and R-phycoerythrin-conjugated streptavidin reporter system. Standard curves were created for quantitative purposes using commercially-available anti-antigen antibodies and permitted analytical performance characteristics to be calculated. These assays were used to preliminarily evaluate a series of pretreatment serum samples from stage IV NSCLC patients receiving anti PD-1/-L1 therapy after failure of at least one prior line of therapy (n = 40) and their classification efficiency calculated based on 12 months overall survival (OS) threshold.

RESULTS

Six assays were developed that each showed dynamic ranges of four orders of magnitude and provided more than 90% classification accuracy based on the observed clinical outcome data. Inter- and intra-assay precision was assessed within these standards and overall %CVs of ≤7% and ≤ 10%, respectively, were calculated. Generally, the baseline level of autoantibodies were significantly (p < 0.05) lower in the ≥12 months survival group relative to the <12 months survival groups. Serum titers of FH, HSD170B, NY-ESO-1, and vimentin were significantly correlated with ≥12 month survival (p-value 0.0038, 0.0061, 0.0073, and 0.022, respectively). IMPDH2 and PGAM1 were found to have marginal significance (p-value 0.08 and 0.076, respectively).

CONCLUSION

This study demonstrates an efficient and promising means for assessing circulating autoantibody titers that could be useful in selecting advanced NSCLC patients for PD-1/-L1 directed immunotherapy. Further exploration and validation of this paradigm is warranted to further refine current treatment selection methods for this therapeutic strategy.

High level of WAVE1 expression is associated with tumor aggressiveness and unfavorable prognosis of epithelial ovarian cancer

OBJECTIVES

Wiskott-Aldrich syndrome protein family verprolin-homologous protein 1 (WAVE1) has been shown to promote cancer invasion and metastasis. However, no evidence has been found to identify the role of WAVE1 in epithelial ovarian cancer (EOC). This study aims to determine the effect of WAVE1 expression and investigate a possible relationship between WAVE1 and prognosis in EOC.

METHODS

WAVE1 protein level was measured in 223 EOC specimens by immunohistochemical staining and 46 EOC specimens by Western blot analysis. Expression of WAVE1 in ovarian cancer cell lines was evaluated by Western blot analysis and immunofluorescence. Survival analysis was performed to assess the correlation between WAVE1 expression and survival.

RESULTS

Immunohistochemical staining and Western blot analysis showed that WAVE1 was overexpressed in EOC compared with samples from a non-invasive ovarian tumor and normal ovaries (P<0.05). Furthermore, expression of WAVE1 was significantly associated with advanced FIGO stage, poor grade, serum Ca-125 and residual tumor size (P<0.05). By Western blot analysis, WAVE1 expression was detected in four ovarian cancer cell lines. Immunofluorescence was performed to demonstrate WAVE1 expression in SKOV3 and 3AO cell lines. Survival analysis showed that patients with low WAVE1 staining had a significantly better survival compared to patients with high WAVE1 staining (P<0.05). In multivariate analysis, WAVE1 overexpression, advanced stage and suboptimal surgical debulking were independent prognostic factors of poor survival.

CONCLUSIONS

Our present study finds that WAVE1 overexpression is associated with an unfavorable prognosis. WAVE1 is an independent prognostic factor for EOC, which suggests that it is a novel and crucial predictor for EOC metastasis.