Hurley, Judith

1098 Background: Leucine-rich repeat-containing protein 15 ( LRRC15) has emerged as a potential biomarker and therapeutic target for various cancers due to its high expression in cancer-associated fibroblasts (CAFs) and role in tumor progression. High LRRC15 expression is associated with poor prognosis in TNBC. This study aims to define the multiomic profile of LRRC15 in TNBC. Methods: 3,038 TNBC samples were analyzed via Next-Generation Sequencing (592, NextSeq; Whole Exome Sequencing, NovaSeq) and Whole Transcriptome Sequencing (NovaSeq; Caris Life Sciences, AZ). Immune cell fractions were estimated using WTS deconvolution (Quantiseq). Stromal cell abundance in the tumor microenvironment (TME) was estimated from RNA expression profiles using MCP Counter. LRRC15 -high (H) and -low (L) tumors were classified by RNA expression above or below the 25th percentile. Real-world overall survival (OS) and treatment-related survival were derived from insurance claims and calculated from tissue collection or treatment initiation to last contact using Kaplan-Meier. Statistical significance was assessed using chi-square and Mann-Whitney U tests with multiple comparison adjustments (q < .05). Results: LRRC15 -H TNBC tumors had higher frequency of PIK3CA (25.9% vs 16.8), PIK3R1 (6.2% vs 1.6%), PTEN (11.3% vs 5.8%), but lower frequency of RB1 (7.8% vs 12.1%) and KMT2D (2% vs 4.4%) compared to LRRC15 -L, all q < 0.05. LRRC15 -H had higher PD-L1 positivity (32.3% vs 24.5%, q < 0.05). Analysis of immune cells showed LRRC15 -H TNBC had higher infiltration of B cells (4.2% vs 3.5%), M1 macrophages (4.3% vs 2%), M2 macrophages (4% vs 2.5%), Tregs (1.9% vs 1.1%), neutrophils (4.9% vs 3.9%), CD8 + T cells (0.4% vs 0.1%), but lower dendritic cells (2.5% vs 3%), all q < 0.05. LRRC15 -H tumors had greater abundance of CAFs (575.6 vs 93.78, 6.14 fold change (FC)) and endothelial cells (7.3 vs 3.7, 1.97 FC), all q < 0.05. LRRC15 -H had higher T-cell inflamed score (71.5 vs -77) and IFNg score (-0.14 vs -1.72), all q < 0.05. LRRC15 -H tumors had higher expression of immune checkpoint genes ( CD274, PDCD1, PDCD1LG2, CTLA4, LAG3, HAVCR2, FOXP3, IDO1, TNFSF14, TIGIT, BTLA, CEACAM1, CD47, CD80, CD86, CD160, CD274 ; FC 1.2-2.5, q < 0.05). LRRC15 -H was associated with better OS (mOS: 24.7 vs 13.6 months; HR 0.61, 95% CI 0.53-0.7, p < 0.001). Post-pembrolizumab survival was longer for LRRC15 -H patients (mOS: 27.2 vs 19.4 months; HR 0.61, 95% CI 0.42-0.89, p = 0.01). Conclusions: LRRC15 -H TNBC exhibited better outcomes with pembrolizumab, likely due to higher immune cell fractions and increased CAFs. These findings highlight TNBC heterogeneity and position LRRC15 as a potential biomarker for tumor stratification, a possible adverse prognostic biomarker and a positive predictive biomarker. Ongoing phase I trials targeting LRRC15 show promise. Combining LRRC15 -targeted therapies with immunotherapy may improve TNBC outcomes, warranting further validation in breast cancer models.

PURPOSETo estimate age-specific relative and absolute cancer risks of breast cancer and to estimate risks of ovarian, pancreatic, male breast, prostate, and colorectal cancers associated with germline PALB2 pathogenic variants (PVs) because these risks have not been extensively characterized.METHODSWe analyzed data from 524 families with PALB2 PVs from 21 countries. Complex segregation analysis was used to estimate relative risks (RRs; relative to country-specific population incidences) and absolute risks of cancers. The models allowed for residual familial aggregation of breast and ovarian cancer and were adjusted for the family-specific ascertainment schemes.RESULTSWe found associations between PALB2 PVs and risk of female breast cancer (RR, 7.18; 95% CI, 5.82 to 8.85; P = 6.5 × 10−76), ovarian cancer (RR, 2.91; 95% CI, 1.40 to 6.04; P = 4.1 × 10−3), pancreatic cancer (RR, 2.37; 95% CI, 1.24 to 4.50; P = 8.7 × 10−3), and male breast cancer (RR, 7.34; 95% CI, 1.28 to 42.18; P = 2.6 × 10−2). There was no evidence for increased risks of prostate or colorectal cancer. The breast cancer RRs declined with age ( P for trend = 2.0 × 10−3). After adjusting for family ascertainment, breast cancer risk estimates on the basis of multiple case families were similar to the estimates from families ascertained through population-based studies ( P for difference = .41). On the basis of the combined data, the estimated risks to age 80 years were 53% (95% CI, 44% to 63%) for female breast cancer, 5% (95% CI, 2% to 10%) for ovarian cancer, 2%-3% (95% CI females, 1% to 4%; 95% CI males, 2% to 5%) for pancreatic cancer, and 1% (95% CI, 0.2% to 5%) for male breast cancer.CONCLUSIONThese results confirm PALB2 as a major breast cancer susceptibility gene and establish substantial associations between germline PALB2 PVs and ovarian, pancreatic, and male breast cancers. These findings will facilitate incorporation of PALB2 into risk prediction models and optimize the clinical cancer risk management of PALB2 PV carriers.

Abstract Breast cancer diagnosis and death has risen in low to middle income countries (LMIC) in the past 20 years. Early detection, diagnosis and treatment in the LMIC setting are thought to impact morbidity and survivorship. The population of South Florida is composed of a significant portion of Afro-Caribbean immigrants from LMICs. We compared a cohort of recent Haitian immigrants with residents in Haiti who had a diagnosis of breast cancer to evaluate the effects of geographical location on presentation, treatment and outcomes. Methods: Retrospective cohort study. Participants were Haitian females with breast cancer that were living in Miami and presented to the University of Miami/Jackson Memorial Hospital (UM/JMH) between 2008 and 2014 and patients living in Haiti and presented to the Breast Cancer Treatment program at the Hospital Bernard Mevs Project Medishare (HBMPM) from 2013 to 2015 with a new diagnosis or who had been diagnosed as far back as 2008 and were presenting for continuation of care. The main outcome was the relationship between cohort location and breast cancer characteristics and cancer–specific survival by log-rank. Cox proportional hazards regression was used to compare breast cancer–specific survival overall and analyzed by stage and other significant explanatory factors. Results: 102 patients from UM/JMH and 94 patients from HBMPM were included in the analysis. The cohort in Haiti presented after longer median duration of symptoms (20 vs 3 months, p&lt;0.001) and more advanced stage (31% Vs 20% with locally advance and 27% vs 19% with metastatic disease). The median age of diagnosis was 55 years in Miami compared to 50 years in Haiti (p=0.03). In Miami all patients had estrogen receptor (ER) and her-2 status ascertained at diagnosis, whereas only 52% and 27% of the Haitian cohort had them. Tumor characteristics in Miami vs Haiti in patients with reported status: ER + 74% (n=102) vs 55% (n=49), p=0.02, her-2+ 20% (n=102) vs 28% (n=25), p=0.36, triple negative 27% (n=102) vs 28% (n=25),p=0.49. Treatment modalities and censoring was available for all the patients in Miami and 72 patients in Haiti. In Haiti, radiation therapy was not widely available compared to Miami. Once patients had known ER and her-2 status, there was no difference in treatment with hormonal therapy (p=0.97) but none of the patients in Haiti received her-2 directed therapy (p&lt;0.001). 50% of the patients with unknown ER status in Haiti received Tamoxifen. Twice as many Haitian women died after a median follow-up of 23 months (12% vs 24%), with median survival of 53 months for Haitians in Haiti (not reached for Miami cohort). Breast cancer specific survival was significantly different in the two cohorts (p&lt;0.000). After exploratory analysis, the risk of death was higher for Haitians in Haiti than Haitians in Miami [HR 3.13 (CI 1.50-6.51)] and was higher for more advanced disease [HR 2.58 (CI 1.67-3.99)]. No other variable or interaction reached statistical significance in our model. Conclusion: Haitian women diagnosed with breast cancer in Haiti experience a significantly worse outcome than Haitians living in Miami that appears to be related to a more advanced stage, younger age, more ER negative tumors and lack of timely effective treatments including restricted access to trastuzumab and radiation. In addition there is a difference in the age of breast cancer onset (Caucasian 62, African American 58, Haitian American 55, Haitian 50) and ER positivity (Caucasian 70%, African American 48%, Haitian American 74%, Haitian 55%) depending on race and ethnic group that raises the question of whether there are disparities within subgroups of women of African origin who have breast cancer. Confounding epigenetic-related variables may impact survival and they need further exploration in these populations. Citation Format: Alexandra Gomez, Vincent DeGennaro, Jr., Sophia George, Estefania Santamaria, Gustavo Westin, Gabriel Dieudina, Judith Hurley. Presentation, treatment, and outcomes of Haitian women with breast cancer in Miami and Haiti: Disparities in breast cancer. A retrospective cohort study. [abstract]. In: Proceedings of the Eighth AACR Conference on The Science of Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; Nov 13-16, 2015; Atlanta, GA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2016;25(3 Suppl):Abstract nr C55.