K. Morrell

On representing the prognostic value of continuous gene expression biomarkers with the restricted mean survival curve.

Motivation Researchers developing biomarkers for cancer prognosis from quantitative gene expression data are often faced with an odd methodological discrepancy: while Coxs proportional hazards model, the appropriate and popular technique, produces a continuous and relative risk score, it is hard to cast the estimate in clear clinical terms like median months of survival and percent of patients affected. To produce a familiar Kaplan-Meier plot, researchers commonly make the decision to dichotomize a continuous (often unimodal and symmetric) score. It is well known in the statistical literature that this procedure induces significant bias. Results We illustrate the liabilities of common techniques for categorizing a risk score and discuss alternative approaches. We promote the use of the restricted mean survival (RMS) and the corresponding RMS curve that may be thought of as an analog to the best fit line from simple linear regression. Conclusions Continuous biomarker workflows should be modified to include the more rigorous statistical techniques and descriptive plots described in this article. All statistics discussed can be computed via standard functions in the Survival package of the R statistical programming language. Example R language code for the RMS curve is presented in the appendix.

Prognostic value of miliary versus non-miliary sub-staging in advanced ovarian cancer

OBJECTIVE The presence of miliary disease during initial ovarian cancer debulking may reflect a distinct mode of peritoneal spread independent from size-based tumor staging and may explain variation in response to treatment and survival outcomes. To infer the prevalence, presentation and clinical implications of miliary disease we reviewed existing surgical records. METHODS Reports were available for 1008 primary debulking surgeries for ovarian, primary peritoneal or fallopian tube cancer between 2001 and 2015 (685 reports from 2005 to 2015). Clinical outcome data was available for 938 patients. We analyzed a high-stage sub-cohort for survival (N=436). RESULTS Most records were evaluable for miliary disease (761/938); for these, the miliary phenotype was highly prevalent (249/761, 32.7%) and often accompanied by ascites (185/249, 74%). While optimal debulking rates were unaffected by miliary disease, total resection (R0) rates were poorer. Liver, stomach, spleen or bladder appeared to be sporadically involved while the omentum, mesentery, bowel, peritoneum and diaphragm were affected simultaneously (Spearman rho>0.5). Overall, miliary disease was associated with worse progression free survival, overall survival, and time from relapse to death independent of stage. Survival effects were particularly strong for Stage IV disease where median overall survival varied by over 30months (log-rank p=0.002). CONCLUSIONS Miliary disease is an identifiable surgical phenotype reflecting a distinct clinical trajectory that adds prognostic information to standard disease burden-based staging. These findings should permit further retrospective investigation in a wider cohort and prompt the consideration of prospective structured operative reporting standards and treatment strategies.

Cancer stem cell and its niche in malignant progression of oral potentially malignant disorders

OBJECTIVE The purpose of this study was to determine association between cancer stem cells (CSCs) and their niche with progression of oral potentially malignant disorders. MATERIALS AND METHODS Patients with histologically confirmed oral potentially malignant disorders, stratified into high/low risk lesions based on the degree of dysplasia and oral cancer were included in this study. Immunohistochemical profiling of markers of CSCs (CD44), endothelial cells (CD31) and CSC-vascular niche cross-talk (CXCR4 and SDF1) were carried out. Statistical analysis was performed to correlate the relationship of markers with histopathology grade (ANOVA, and χ2 test, unpaired t test) using GraphPad InStat v3.06. RESULTS The study included 550 samples (349 patients) and analysis showed progressive increase in expression levels of CSC and its niche markers with increase in grade of dysplasia as compared to the normal cohort (p < 0.05). Co-expression analysis revealed that, in comparison to the normal cohort, a larger percentage of patients showed increased expression of CD31 and CD44 (CD31high/CD44high; p < 0.05) and of CXCR4 and SDF1 (CXCR4high/SDF1high; p = 0.04), suggesting an association of the CSCs and the vascular niche. Further, distribution of patients with CD44high/CXCR4high (p < 0.05) and CD31high/SDF1high (p = 0.01) was significantly increased in the high-risk group (18%), suggesting a correlation between CD44+/CXCR4+ cells, the vascular niche and progression of oral dysplastic lesions. CONCLUSION The increased expression of CSCs, the vascular niche and their cross talk markers are associated with increase in severity of dysplasia suggesting their role in the progression of oral potentially malignant disorders and may hence be used in identifying high-risk OPMD.

Impact of ascites volume on clinical outcomes in ovarian cancer: A cohort study

OBJECTIVES To investigate the impact of ascites volume on ovarian cancer outcomes. METHODS Clinicopathologic features of a cohort of patients with ovarian cancer were obtained from a curated database at a single institution. Progression free survival (PFS) and overall survival (OS) were recorded. Ascites volume at primary surgery was dichotomized at 2000mL and comparisons for high and low volume ascites were made. Additionally, to elucidate interactions between ascites and ovarian tumor progression, we evaluated the effect of intraperitoneal administrations of murine cell-free ascites versus saline in a syngeneic mouse model of epithelial ovarian cancer. RESULTS Out of 685 patients identified, 58% had ascites present at the time of initial surgery. Considering the volume of ascites continuously, each liter of ascites was associated with shorter PFS (HR=1.12, 95% CI: 1.07-1.17) and OS (HR=1.12, 95%CI: 1.07-1.17). Patients with ascites greater than the median of 2000mL had significantly shorter PFS (14.5months vs. 22.7months; p<0.001) and OS (27.7months vs. 42.9months; p<0.001). After adjusting for stage, presence of ascites was inversely associated with ability to achieve optimal cytoreductive surgery. Consistent with these correlative results in patients, intraperitoneal administrations of murine cell-free ascites accelerated ovarian cancer progression in mice. CONCLUSIONS The volume of ascites at initial diagnosis of ovarian cancer correlated with worse PFS and OS. The effect of large volume on prognosis is likely to be in part related to reduced likelihood for complete resection of tumor (R0). If these findings are confirmed in independent studies, consideration should be made to add the presence of large volume ascites at diagnosis to the staging criteria for ovarian cancer.

Abstract B10: Increased expression of EZH2 and TOP2A predicts for a poorer prognostic outcome in Genitourinary Cancers

The enhancer of Zeste homolog 2 (EZH2), a component of the Polycomb Repressive Complex 2 (PRC2), is an epigenetic silencer that is known to be highly expressed in both metastatic and primary prostate cancer (PCa). More recently, topoisomerase IIα (TOP2A), an enzyme that controls the topologic states of DNA during the cell cycle, has also been identified as being highly expressed in PCa. Both EZH2 and TOP2A have been associated with more aggressive disease and poorer prognostic outcome. During genome-wide analysis, using The Cancer Genome Atlas (TCGA), EZH2 and Top2A were found to be highly positively correlated, most noticeably in PCa and clear cell Renal Cell Carcinoma (ccRCC). As a result, we predicted increased expression of both EZH2 and TOP2A in an individual, would predict for a worse prognostic outcome than either gene being highly expressed alone. Further analysis of the TCGA and Memorial Sloan Kettering Cancer Center (MSKCC) datasets, demonstrated that increased expression of these two genes predicted for a poorer prognostic outcome in genitourinary cancers. In tumor samples with increased expression of EZH2 and TOP2A, as compared to the tumor samples that did not concurrently overexpress both EZH2 and TOP2A, patients displayed worse overall Regression Free Survival (RFS), which were associated with increase hazard ratio, and tumor staging and grades. . As these poor prognostic markers were consistent across multiple cancer subtypes, we are beginning to explore those genes that are differentially expressed in individuals with concurrent high TOP2A and EZH2 as a means of further characterizing this novel phenotype. Since these two genes are targetable by drugs such as etoposide (a TOP2 poison) and DZNep (an EZH2 inhibitor), it makes them attractive candidates for treatment in those individuals who not only have tumors that highly express these two genes, but also those individuals that have exacerbated existing treatment options. Citation Format: Spencer Rosario, Zafardjan Dalimov, Jason Kirk, Kayla Morrell, Kevin Eng, Leigh Ellis. Increased expression of EZH2 and TOP2A predicts for a poorer prognostic outcome in Genitourinary Cancers. [abstract]. In: Proceedings of the AACR Special Conference on Chromatin and Epigenetics in Cancer; Sep 24-27, 2015; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2016;76(2 Suppl):Abstract nr B10.