Association of genetic ancestry with colorectal tumor location in Puerto Rican Latinos.

BACKGROUND: Colorectal cancer (CRC) is the first cause of cancer deaths among Puerto Ricans. The incidence and mortality of CRC in Puerto Rico continue to be on the rise. The burden of CRC in Puerto Rico is higher than among US Hispanics and is second only to African Americans, thus supporting the importance of studying this CRC health disparity. The genetic background of the Puerto Rican population is a mix of European, African, and Amerindian races, which may account, in part, for the differences observed in the CRC mortality rates among Puerto Ricans. The objective of the study was to assess the role of genetic ancestry in CRC risk and its association with clinicopathological features of CRC tumors in Puerto Ricans. RESULTS: We used a validated panel of 105 ancestry informative markers (AIMs) to estimate genetic ancestry in 406 Puerto Rican CRC cases and 425 Puerto Rican controls. We examined the association of genetic ancestry with CRC risk and tumor clinicopathological characteristics. CONCLUSIONS: The mean ancestry proportions in the study population were 61% European, 21% African, and 18% Amerindian. No association was observed between genetic ancestry and risk of CRC. However, African ancestry was associated with an increased risk of developing rectal tumors (OR = 1.55, 95% CI 1.04-2.31). Additional studies are needed to fully elucidate the role of African ancestry in CRC carcinogenesis.

Clinical Cancer Genetics Disparities among Latinos.

The three major hereditary cancer syndromes in Latinos (Hereditary Breast and Ovarian Cancer, Familial Adenomatous Polyposis and Lynch Syndrome) have been shown to exhibit geographic disparities by country of origin suggesting admixture-based disparities. A solid infrastructure of clinical genetics geared towards diagnosis and prevention could aid in reducing the mortality of these cancer syndromes in Latinos. Currently, clinical cancer genetic services in Latin America are scarce. Moreover, limited studies have investigated the mutational spectrum of these cancer syndromes in Latinos resulting in gaps in personalized medicine affecting diagnosis, treatment and prevention. The following commentary discusses available genotype and clinical information on hereditary cancer in Latinos and highlights the limited access for cancer genetic services in Latin America including barriers to genetic testing and alternatives for providing better access to genetic services. In this review, we discuss the status of clinical genetic cancer services for both US Latinos and those Latinos living in Latin America.

Hereditary cancer syndromes in Latino populations: genetic characterization and surveillance guidelines.

Hereditary cancer predisposition syndromes comprise approximately 10% of diagnosed cancers; however, familial forms are believed to account for up to 30% of some cancers. In Hispanics, the most commonly diagnosed hereditary cancers include colorectal cancer syndromes such as, Lynch Syndrome, Familial Adenomatous Polyposis, and hereditary breast and ovarian cancer syndromes. Although the incidence of hereditary cancers is low, patients diagnosed with hereditary cancer syndromes are at high-risk for developing secondary cancers. Furthermore, the productivity loss that occurs after cancer diagnosis in these high-risk patients has a negative socio-economic impact. This review summarizes the genetic basis, phenotype characteristics, and the National Comprehensive Cancer Network's screening, testing, and surveillance guidelines for the leading hereditary cancer syndromes. The aim of this review is to promote a better understanding of cancer genetics and genetic testing in Hispanic patients.