Darl D. Flake

Prognostic value of an RNA expression signature derived from cell cycle proliferation genes in patients with prostate cancer: a retrospective study

BACKGROUND Optimum management of clinically localised prostate cancer presents unique challenges because of the highly variable and often indolent natural history of the disease. To predict disease aggressiveness, clinicians combine clinical variables to create prognostic models, but the models have limited accuracy. We assessed the prognostic value of a predefined cell cycle progression (CCP) score in two cohorts of patients with prostate cancer. METHODS We measured the expression of 31 genes involved in CCP with quantitative RT-PCR on RNA extracted from formalin-fixed paraffin-embedded tumour samples, and created a predefined score and assessed its usefulness in the prediction of disease outcome. The signature was assessed retrospectively in a cohort of patients from the USA who had undergone radical prostatectomy, and in a cohort of randomly selected men with clinically localised prostate cancer diagnosed by use of a transurethral resection of the prostate (TURP) in the UK who were managed conservatively. The primary endpoint was time to biochemical recurrence for the cohort of patients who had radical prostatectomy, and time to death from prostate cancer for the TURP cohort. FINDINGS After prostatectomy, the CCP score was useful for predicting biochemical recurrence in the univariate analysis (hazard ratio for a 1-unit change [doubling] in CCP 1·89; 95% CI 1·54-2·31; p=5·6×10(-9)) and the best multivariate analysis (1·77, 1·40-2·22; p=4·3×10(-6)). In the best predictive model (final multivariate analysis), the CCP score and prostate-specific antigen (PSA) concentration were the most important variables and were more significant than any other clinical variable. In the TURP cohort, the CCP score was the most important variable for prediction of time to death from prostate cancer in both univariate analysis (2·92, 2·38-3·57, p=6·1×10(-22)) and the final multivariate analysis (2·57, 1·93-3·43; p=8·2×10(-11)), and was stronger than all other prognostic factors, although PSA concentration also added useful information. Heterogeneity in the hazard ratio for the CCP score was not noted in any case for any clinical variables. INTERPRETATION The results of this study provide strong evidence that the CCP score is a robust prognostic marker, which, after additional validation, could have an essential role in determining the appropriate treatment for patients with prostate cancer. FUNDING Cancer Research UK, Queen Mary University of London, Orchid Appeal, US National Institutes of Health, and Koch Foundation.

Somatic Mutations in BRCA1 and BRCA2 Could Expand the Number of Patients That Benefit From Poly (ADP Ribose) Polymerase Inhibitors in Ovarian Cancer

PURPOSE The prevalence of BRCA(1/2) mutations in germline DNA from unselected ovarian cancer patients is 11% to 15.3%. It is important to determine the frequency of somatic BRCA(1/2) changes, given the sensitivity of BRCA-mutated cancers to poly (ADP ribose) polymerase-1 (PARP1) inhibitors and platinum analogs. PATIENTS AND METHODS In 235 unselected ovarian cancers, BRCA(1/2) was sequenced in 235, assessed by copy number analysis in 95, and tiling arrays in 65. 113 tumors were sequenced for TP53. BRCA(1/2) transcript levels were assessed by quantitative polymerase chain reaction in 220. When available for tumors with BRCA(1/2) mutations, germline DNA was sequenced. RESULTS Forty-four mutations (19%) in BRCA1 (n = 31)/BRCA2 (n = 13) were detected, including one homozygous BRCA1 intragenic deletion. BRCA(1/2) mutations were particularly common (23%) in high-grade serous cancers. In 28 patients with available germline DNA, nine (42.9%) of 21 and two (28.6%) of seven BRCA1 and BRCA2 mutations were demonstrated to be somatic, respectively. Five mutations not previously identified in germline DNA were more commonly somatic than germline (four of 11 v one of 17; P = .062). There was a positive association between BRCA1 and TP53 mutations (P = .012). BRCA(1/2) mutations were associated with improved progression-free survival (PFS) after platinum-based chemotherapy in univariate (P = .032; hazard ratio [HR] = 0.65; 95% CI, 0.43 to 0.98) and multivariate (P = .019) analyses. BRCA(1/2) deficiency, defined as BRCA(1/2) mutations or expression loss (in 24 [13.3%] BRCA(1/2)-wild-type cancers), was present in 67 ovarian cancers (30%) and was also significantly associated with PFS in univariate (P = .026; HR = 0.67; 95% CI, 0.47 to 0.96) and multivariate (P = .008) analyses. CONCLUSION BRCA(1/2) somatic and germline mutations and expression loss are sufficiently common in ovarian cancer to warrant assessment for prediction of benefit in clinical trials of PARP1 inhibitors.

BRCA1/2 mutations and expression: Response to platinum chemotherapy in patients with advanced stage epithelial ovarian cancer

OBJECTIVE Our objective was to determine the rate of BRCA1/2 deficiency in platinum-sensitive and platinum-resistant tumors from a cohort of unselect patients with advanced epithelial ovarian cancer (EOH). METHODS BRCA1/2 mutation analysis was performed in 29 patients with platinum-sensitive EOC and 24 patients with platinum-resistant disease. Germline DNA was analyzed in mutation carriers when normal tissue was available. BRCA expression was ascertained by quantitative rt-PCR. Associations between BRCA mutation status and expression levels and parameters of platinum response were analyzed. RESULTS Fifteen of 53 (28.3%) EOC tumors had BRCA1/2 mutations. Twelve mutations were in BRCA1, while 3 involved BRCA2. Of the 12 mutation-carriers with normal tissue available for DNA analyses, 33.3% of the mutations were found to be somatic. Three mutations were novel. The majority of BRCA mutations (73%) were identified in patients with platinum-sensitive disease. In total, 38% of platinum-sensitive tumors were found to have a BRCA mutation, compared to 17% of the platinum-resistant patients. A statistical trend toward platinum-sensitive disease was seen in BRCA mutation carriers (p=0.079). Nineteen (36%) study patients had some form of BRCA deficiency, and these patients were less likely to have platinum-resistant tumors (OR=0.29; p value=0.048). CONCLUSIONS BRCA mutations occurred more frequently in platinum-sensitive EOC than platinum-resistant disease. The high overall frequency of BRCA deficiency in EOC underscores the importance of tumor profiling as therapies targeting the DNA repair pathway are being investigated.

Clinical validation of a gene expression signature that differentiates benign nevi from malignant melanoma

Histopathologic examination is sometimes inadequate for accurate and reproducible diagnosis of certain melanocytic neoplasms. As a result, more sophisticated and objective methods have been sought. The goal of this study was to identify a gene expression signature that reliably differentiated benign and malignant melanocytic lesions and evaluate its potential clinical applicability. Herein, we describe the development of a gene expression signature and its clinical validation using multiple independent cohorts of melanocytic lesions representing a broad spectrum of histopathologic subtypes.

An independent validation of a gene expression signature to differentiate malignant melanoma from benign melanocytic nevi

Recently, a 23‐gene signature was developed to produce a melanoma diagnostic score capable of differentiating malignant and benign melanocytic lesions. The primary objective of this study was to independently assess the ability of the gene signature to differentiate melanoma from benign nevi in clinically relevant lesions.

Analytical validation of a melanoma diagnostic gene signature using formalin- fixed paraffin-embedded melanocytic lesions

AIM These studies were to validate the analytical performance of a gene expression signature that differentiates melanoma and nevi, using RNA expression from 14 signature genes and nine normalization genes that generates a melanoma diagnostic score (MDS). MATERIALS & METHODS Formalin-fixed paraffin-embedded melanocytic lesions were evaluated in these studies. RESULTS The overall SD of the assay was determined to be 0.69 MDS units. Individual amplicons within the signature had an average amplification efficiency of 92% and a SD less than 0.5 CT. The MDS was reproducible across a 2000-fold dilution range of input RNA. Melanin, an inhibitor of PCR, does not interfere with the signature. CONCLUSION These studies indicate this signature is robust and reproducible and is analytically validated on formalin-fixed paraffin-embedded melanocytic lesions.

Diagnostic Distinction of Malignant Melanoma and Benign Nevi by a Gene Expression Signature and Correlation to Clinical Outcomes

Background: Histopathologic examination alone can be inadequate for diagnosis of certain melanocytic neoplasms. Recently, a 23-gene expression signature was clinically validated as an ancillary diagnostic test to differentiate benign nevi from melanoma. The current study assessed the performance of this test in an independent cohort of melanocytic lesions against clinically proven outcomes. Methods: Archival tissue from primary cutaneous melanomas and melanocytic nevi was obtained from four independent institutions and tested with the gene signature. Cases were selected according to pre-defined clinical outcome measures. Malignant lesions were defined as stage I–III primary cutaneous melanomas that produced distant metastases (metastatic to sites other than proximal sentinel lymph node(s)) following diagnosis of the primary lesion. Melanomas that were metastatic at the time of diagnosis, all re-excisions, and lesions with <10% tumor volume were excluded. Benign lesions were defined as cutaneous melanocytic lesions with no adverse long-term events reported. Results: Of 239 submitted samples, 182 met inclusion criteria and produced a valid gene expression result. This included 99 primary cutaneous melanomas with proven distant metastases and 83 melanocytic nevi. Median time to melanoma metastasis was 18 months. Median follow-up time for nevi was 74.9 months. The gene expression score differentiated melanoma from nevi with a sensitivity of 93.8% and a specificity of 96.2%. Conclusions: The results of gene expression testing closely correlate with long-term clinical outcomes of patients with melanocytic neoplasms. Impact: Collectively, this provides strong evidence that the gene signature adds valuable adjunctive information to aid in the accurate diagnosis of melanoma. Cancer Epidemiol Biomarkers Prev; 26(7); 1107–13. ©2017 AACR.

Abstract P4-11-15: Risk stratification within luminal B breast cancer using a second generation prognostic RNA signature

Background: Indication to adjuvant chemotherapy in early stage ER-positive breast cancer is usually based on clinico-pathological parameters, and has been recently improved by the introduction of prognostic expression profiles. Clinical or molecular features are efficient in identifying low-risk (pT1, histological grade 1, pN0, low RS, Luminal A subtype) and high-risk patients (>pT1, grade 3, N2, high RS). However, a large group of patients with intermediate clinical or molecular characteristic (grade 2, intermediate RS, luminal B) fall into the category between distinctly low and distinctly high risk and receive no treatment guidance from current decision tools. Methods: From a population of 1929 chemo-naive, hormone treated, luminal B (Her-2 negative), pT1-pT3, pN0-N1a breast cancer patients diagnosed and treated at the European Institute of Oncology from 1997 to 2005, we selected a random subcohort of 555 cases, in a case-cohort design. All the patients with local or distant metastasis which were not already included were added to the subcohort, leading to a total of 704 patients (208 with local or distant recurrences and 496 random controls). Luminal B status was determined by the immunohistochemical analysis of ER, PgR, HER2 and Ki-67, according to the 2011 St. Gallen criteria. FFPE sections of the primary tumor were analyzed for the mRNA expression of 43 genes by multiplex quantitative PCR. A molecular score (MS) was calculated from the average expression of 23 cell cycle progression genes, the average expression of seven lymphocyte specific genes and the expression of PR and ABCC5, based on a model derived from an independent training cohort. A combined score of MS and the clinical variables of tumor size, grade and node status was modeled in the training cohort and applied to the Luminal B set. The association between MS and the risk of distant metastasis was evaluated in a weighted multivariable Cox regression model, adjusted for traditional clinical factors and Ki-67 labeling index (LI). Results: 640 samples, including 102 distant metastasis, had full clinical and expression data. In the 500 samples from the subcohort, median Ki67 LI was 21% (IQR=11%, Q1=16%, Q3=27%). Either one unit increase of Ki-67 LI (HR 1.06, 95%CI (1.04-1.08), p Conclusions: The MS provides important prognostic discrimination beyond traditional clinico-pathological characteristics, including Ki-67 LI, in Luminal B breast cancer, and contributes in identifying a subset of patients which may be successfully treated with endocrine therapy only. Citation Format: Giancarlo Pruneri, Vincenzo Bagnardi, Davide Disalvatore, Giuseppe Curigliano, Nicole Rotmensz, Carmen Criscitiello, Darl D Flake II, Susanne Wagner, Alexander Gutin, Jerry Lanchbury, Massimo Barberis, Francesca Lombardi, Giuseppe Viale. Risk stratification within luminal B breast cancer using a second generation prognostic RNA signature [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr P4-11-15.