Molecular Epidemiology Laboratory of the Division of Epidemiology and Biostatistics, Department of Internal Medicine, University of New Mexico Health Sciences Center, School of Medicine, Albuquerque, New Mexico, United States of America.
PLoS One. 2011;6(8):e23950. doi: 10.1371/journal.pone.0023950. Epub 2011 Aug 29.
Hispanics are known to be an extremely diverse and genetically admixed ethnic group. The lack of methodologies to control for ethnicity and the unknown admixture in complex study populations of Hispanics has left a gap in understanding certain cancer disparity issues. Incidence rates for oral and pharyngeal cancer (OPC) in Puerto Rico are among the highest in the Western Hemisphere. We conducted an epidemiological study to examine risk and protective factors, in addition to possible genetic susceptibility components, for oral cancer and precancer in Puerto Rico.
METHODOLOGY/PRINCIPAL FINDINGS: We recruited 310 Puerto Rico residents who had been diagnosed with either an incident oral squamous cell carcinoma, oral precancer, or benign oral condition. Participants completed an in-person interview and contributed buccal cells for DNA extraction. ABI Biosystem Taqman™ primer sets were used for genotyping 12 ancestry informative markers (AIMs). Ancestral group estimates were generated using maximum likelihood estimation software (LEADMIX), and additional principal component analysis was carried out to detect population substructures. We used unconditional logistic regression to assess the contribution of ancestry to the risk of being diagnosed with either an oral cancer or precancer while controlling for other potential confounders. The maximum likelihood estimates showed that study participants had a group average ancestry contribution of 69.9% European, 24.5% African, and 5.7% detectable Native American. The African and Indigenous American group estimates were significantly higher than anticipated. Neither self-identified ethnicity nor ancestry markers showed any significant associations with oral cancer/precancer risk in our study.
CONCLUSIONS/SIGNIFICANCE: The application of ancestry informative markers (AIMs), specifically designed for Hispanics, suggests no hidden population substructure is present based on our sampling and provides a viable approach for the evaluation and control of ancestry in future studies involving Hispanic populations.
众所周知，西班牙裔是一个极其多样化且基因混合的族群。由于缺乏控制族群的方法，以及西班牙裔复杂研究人群中未知的混合情况，这导致人们对某些癌症差异问题的理解存在空白。波多黎各的口腔和口咽癌（OPC）发病率是西半球最高的。我们进行了一项流行病学研究，以检查波多黎各口腔癌和癌前病变的风险和保护因素，以及可能的遗传易感性因素。
方法/主要发现：我们招募了 310 名波多黎各居民，他们被诊断患有口腔鳞状细胞癌、口腔癌前病变或良性口腔疾病。参与者完成了面对面的访谈，并提供了口腔细胞用于 DNA 提取。ABI Biosystem Taqman™ 引物组用于对 12 个种族信息标记物（AIMs）进行基因分型。使用最大似然估计软件（LEADMIX）生成祖先群体估计值，并进行额外的主成分分析以检测群体亚结构。我们使用无条件逻辑回归来评估祖先对被诊断患有口腔癌或癌前病变的风险的贡献，同时控制其他潜在的混杂因素。最大似然估计表明，研究参与者的平均祖先贡献为 69.9%欧洲人、24.5%非洲人和 5.7%可检测的美洲原住民。非洲和土著美洲人的估计值明显高于预期。在我们的研究中，自我认同的种族或祖先标记均与口腔癌/癌前病变风险没有显著关联。
结论/意义：应用专为西班牙裔设计的种族信息标记物（AIMs）表明，根据我们的抽样，不存在隐藏的群体亚结构，为评估和控制未来涉及西班牙裔人群的研究中的祖先提供了可行的方法。
