You will be shown an abstract from a biomedical research paper. Given this abstract, your task is to extract all unique entities of the following types: ["Chemical"].

Please return the output as a JSON object of the format: {"Chemical": ["Arsenic", ...]}. The keys should be entity types and values should be lists of extracted entities belonging to the corresponding type. If you cannot find entities belonging to a specific type, the value should be [].

Only output the JSON object and do not include any additional text.

Abstract:

Genetic Variants in 2q31 and 5p15 Are Associated With Aggressive Benign Prostatic Hyperplasia in a Chinese Population. BACKGROUND: Benign prostatic hyperplasia (BPH) is a common disease prevalent in elderly men. However, the genetic determinants of BPH remain unclear. Because BPH and prostate cancer (PCa) share some common pathological characteristics, we investigated whether susceptibility loci for PCa contributed to BPH risk and BPH aggressiveness in Chinese men. METHODS: Fourteen SNPs associated with PCa risk in a Chinese population were genotyped in 426 BPH cases (184 aggressive and 242 non-aggressive BPH cases) and 1,008 controls. The association between the SNPs and BPH risk/aggressiveness was estimated using logistic regression analysis. In addition, effects of the 14 SNPs on BPH related clinical traits, including International Prostate Symptom Score (IPSS), prostate volume, total PSA, and free PSA were evaluated using linear regression analysis. RESULTS: Two SNPs, rs12621278 in ITGA6 at 2q31 (OR = 0.82, P = 0.05) and rs339331 in RFX6 at 6q22 (OR = 1.22, P = 0.04) were significantly associated with BPH. In addition, rs12621278 (OR = 0.73, P = 0.05) and rs12653946, 13 kb upstream of IRX4 at 5p15 (OR = 1.40, 0.03), were significantly associated with aggressive BPH. Moreover, the risk allele of rs12621278 (G) and rs12653946 (T) for aggressive BPH were significantly associated with elevated IPSS after treatment (P = 0.01). CONCLUSIONS: This is the first systematic investigation on the contributions of PCa susceptibility loci to risk and aggressiveness of BPH. Our findings advance our understanding of the genetic basis of BPH, especially aggressive BPH. In addition, our results provide new insights into the genetic determinants shared between BPH and PCa. Prostate 9999:XX-XX. © 2013 Wiley Periodicals, Inc.
{"Chemical": []}