title: Influence of race on microsatellite instability and CD8+ T cell infiltration in colon cancer.
abstract: African American patients with colorectal cancer show higher mortality than their Caucasian counterparts. Biology might play a partial role, and prior studies suggest a higher prevalence for microsatellite instability (MSI) among cancers from African Americans, albeit patients with MSI cancers have improved survival over patients with non-MSI cancers, counter to the outcome observed for African American patients. CD8+ T cell infiltration of colon cancer is postively correlated with MSI tumors, and is also related to improved outcome. Here, we utilized a 503-person, population-based colon cancer cohort comprising 45% African Americans to determine, under blinded conditions from all epidemiological data, the prevalence of MSI and associated CD8+ T cell infiltration within the cancers. Among Caucasian cancers, 14% were MSI, whereas African American cancers demonstrated 7% MSI (P = 0.009). Clinically, MSI cancers between races were similar; among microsatellite stable cancers, African American patients were younger, female, and with proximal cancers. CD8+ T cells were higher in MSI cancers (88.0 vs 30.4/hpf, P<0.0001), but was not different between races. Utilizing this population-based cohort, African American cancers show half the MSI prevalence of Caucasians without change in CD8+ T cell infiltration which may contribute towards their higher mortality from colon cancer.
authors: Division of Gastroenterology, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan, United States of America; Department of Medicine, University of California San Diego, San Diego, California, United States of America; Moores Cancer Center, University of California San Diego, San Diego, California, United States of America.
authors: John M
authors: JM
authors: Carethers
authors: Department of Biology, Molecular Biology Institute, San Diego State University, San Diego, California, United States of America.
authors: Bhavya
authors: B
authors: Murali
authors: Department of Biology, Molecular Biology Institute, San Diego State University, San Diego, California, United States of America.
authors: Bing
authors: B
authors: Yang
authors: Department of Medicine, University of California San Diego, San Diego, California, United States of America.
authors: Ryan T
authors: RT
authors: Doctolero
authors: Department of Medicine, University of California San Diego, San Diego, California, United States of America.
authors: Akihiro
authors: A
authors: Tajima
authors: Department of Biology, Molecular Biology Institute, San Diego State University, San Diego, California, United States of America.
authors: Ranor
authors: R
authors: Basa
authors: Department of Medicine, University of California San Diego, San Diego, California, United States of America.
authors: E Julieta
authors: EJ
authors: Smith
authors: Department of Biology, Molecular Biology Institute, San Diego State University, San Diego, California, United States of America.
authors: Monte
authors: M
authors: Lee
authors: Department of Biology, Molecular Biology Institute, San Diego State University, San Diego, California, United States of America.
authors: Ryan
authors: R
authors: Janke
authors: Department of Biology, Molecular Biology Institute, San Diego State University, San Diego, California, United States of America.
authors: Tina
authors: T
authors: Ngo
authors: Department of Biology, Molecular Biology Institute, San Diego State University, San Diego, California, United States of America.
authors: Ruth
authors: R
authors: Tejada
authors: Graduate School Public Health, San Diego State University, San Diego, California, United States of America.
authors: Ming
authors: M
authors: Ji
authors: Department of Biology, Molecular Biology Institute, San Diego State University, San Diego, California, United States of America.
authors: Matthew
authors: M
authors: Kinseth
authors: Department of Medicine, University of California San Diego, San Diego, California, United States of America.
authors: Betty L
authors: BL
authors: Cabrera
authors: Department of Pathology, University of California San Diego, San Diego, California, United States of America.
authors: Katsumi
authors: K
authors: Miyai
authors: Department of Medicine, University of North Carolina, Chapel Hill, North Carolina, United States of America.
authors: Temitope O
authors: TO
authors: Keku
authors: Department of Medicine, University of North Carolina, Chapel Hill, North Carolina, United States of America.
authors: Christopher F
authors: CF
authors: Martin
authors: Department of Epidemiology, University of North Carolina, Chapel Hill, North Carolina, United States of America.
authors: Joseph A
authors: JA
authors: Galanko
authors: Department of Medicine, University of North Carolina, Chapel Hill, North Carolina, United States of America; Department of Epidemiology, University of North Carolina, Chapel Hill, North Carolina, United States of America.
authors: Robert S
authors: RS
authors: Sandler
authors: Department of Biology, Molecular Biology Institute, San Diego State University, San Diego, California, United States of America.
authors: Kathleen L
authors: KL
authors: McGuire
mesh_terms: D001741:Black or African American / Q000235:genetics*; D000368:Aged; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology*; D016022:Case-Control Studies; D003110:Colonic Neoplasms / Q000208:ethnology* / Q000235:genetics / Q000276:immunology; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D007124:Immunoenzyme Techniques; D016246:Lymphocytes, Tumor-Infiltrating; D008297:Male; D053842:Microsatellite Instability; D008875:Middle Aged; D016133:Polymerase Chain Reaction; D011446:Prospective Studies; D014481:United States / Q000453:epidemiology; D044465:White People / Q000235:genetics*