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Circulating blood CD34(+) cells consist of hematopoietic stem/progenitor cells, angiogenic cells, and endothelial cells. In addition to their clinical use in hematopoietic stem cell transplantation, CD34(+) cells may also promote therapeutic neovascularization. Therefore, understanding the factors that influence circulating CD34(+) cell frequency has wide implications for vascular biology in addition to stem cell transplantation. In the present study, we examined the clinical and genetic characteristics associated with circulating CD34(+) cell frequency in a large, community-based sample of 1786 Framingham Heart Study participants.Among subjects without cardiovascular disease (n = 1595), CD34(+) frequency was inversely related to older age, female sex, and smoking. CD34(+) frequency was positively related to weight, serum total cholesterol, and statin therapy. Clinical covariates accounted for 6.3% of CD34(+) variability. CD34(+) frequency was highly heritable (h(2) = 54%; P < .0001). Genome-wide association analysis of CD34(+) frequency identified suggestive associations at several loci, including OR4C12 (chromosome 11; P = 6.7 × 10(-7)) and ENO1 and RERE (chromosome 1; P = 8.8 × 10(-7)). CD34(+) cell frequency is reduced in older subjects and is influenced by environmental factors including smoking and statin use. CD34(+) frequency is highly heritable. The results of the present study have implications for therapies that use CD34(+) cell populations and support efforts to better understand the genetic mechanisms that underlie CD34(+) frequency.

Introduction: Cancer affects people of all races in the U.S.; however, the burden is greater for minority populations. This is influenced by factors such as demographics, behavioral factors, and access to medical services. The disparity is well documented in some solid tumors. However, little information exists on a racial disparity in survival among minority populations diagnosed with chronic myeloid leukemia (CML) especially in the era of targeted therapies. A better understanding of the population impact of CML will drive further research into approaches to improve overall outcomes. Methods: All cases of CML diagnosed between 1973 and 2017 and with available follow-up data reported in the Surveillance, Epidemiology, and End Results database were reviewed. We performed a population-based study of CML to evaluate survival by race and calendar year of diagnosis: 1975-1989 (the era of cytotoxic therapy; busulfan and hydroxyurea), 1990-2000 (the era of Allogeneic hematopoietic stem cell transplantation or interferon-alfa ± cytarabine), and 2001-2015 (the era of targeted therapy; Tyrosine Kinase Inhibitors). Results: A total of 14572 (56.4% were females) patients diagnosed with CML were included in our analysis. The racial distribution was 83.4% white, 10% black, 0.8% American Indian/Alaska Native and 5.9% Asian or Pacific Islander. 5314 (36.5%), 3725 (25.5%) and 5544 (38%) cases of CML were diagnosed during the 1975-1989, 1990-2000 and 2001-2015 eras respectively. The median 5-year survival improved by race with each era, with the greatest improvement observed among patients diagnosed during the 2001-2015 era. Although a trend of improvement in the median 5-year survival is seen across all age categories, patients 65 years and older continue to experience only a modest survival benefit in the era of targeted therapies (Table 1). No significant differences in survival by race was observed in the era of targeted therapies (Figure 1). Conclusions: This survival analysis includes a longer follow-up duration (Diagnosis Years: 1973-2015) for patients with CML compared to prior studies. Although an overall improvement in median survival is seen across all age groups and by each era, survival benefits are lagging in certain populations (black and American Indian/ Alaska Native) older than 65. SEER database captures information from metropolitan counties in the United States and this may not truly reflect the health of the entire US population. Disclosures No relevant conflicts of interest to declare.