A meta-analysis of MSI frequency and race in colorectal cancer.
OBJECTIVE
African Americans (AA) are at a higher risk of colorectal cancer (CRC) and some studies report a higher frequency of microsatellite instability (MSI) in this population while others report lower frequency compared to Caucasians.


OBJECTIVE
To determine and evaluate the association of race and clinical factors with MSI frequency through meta- analysis.


METHODS
Twenty-two studies out of 15,105 (1997-2015) were evaluated after a search in different literature databases, using keywords "colorectal cancer, microsatellite instability, African Americans, Caucasians and Hispanics". We used random effect meta-analysis to calculate the MSI frequency in all studies as well as in African American and Caucasian samples. Meta-regression analysis was used to assess the univariate effect of race, gender, age, tumor location and stage on MSI frequency.


RESULTS
The overall MSI frequency among CRCs was 17% (95%CI: 15%-19%, I²=91%). In studies with available race data, The MSI rate among AAs, Hispanics and Caucasians were 12%, 12% and 14% respectively and was not significantly different. Sub-group analysis of studies with racial information indicates MSI OR of 0.78 for AAs compared to Caucasians.


CONCLUSIONS
CRCs demonstrate an overall MSI frequency of 17%. MSI frequency differences between AAs and Caucasians were not pronounced, suggesting that other factors contribute to the racial disparity. The methodological approaches and biological sources of the variation seen in MSI frequency between different studies need to be further investigated.
Department of Medicine and Cancer Center, Howard University College of Medicine, Washington DC, USA.
Hassan
H
Ashktorab
Department of Pathology, Howard University College of Medicine, Washington DC, USA.
Sadhna
S
Ahuja
Department of Medicine and Cancer Center, Howard University College of Medicine, Washington DC, USA.
Lakshmi
L
Kannan
Department of Medicine and Cancer Center, Yale University, New Haven, CT, USA.
Xavier
X
Llor
Cancer Biology Research Program, The University of Arizona Cancer Center, Tucson, AZ, USA.
Nathan A
NA
Ellis
Department of Medicine and Cancer Center, Yale University, New Haven, CT, USA.
Rosa M
RM
Xicola
Department of Medicine and Cancer Center, Howard University College of Medicine, Washington DC, USA.
Adeyinka O
AO
Laiyemo
Division of Gastroenterology, Department of Internal Medicine, University of Michigan, Ann Arbor, MI, USA.
John M
JM
Carethers
Department of Pathology, Howard University College of Medicine, Washington DC, USA.
Hassan
H
Brim
Department of Medicine and Cancer Center, Howard University College of Medicine, Washington DC, USA.
Mehdi
M
Nouraie
D015179:Colorectal Neoplasms / Q000235:genetics* / Q000473:pathology; D006801:Humans; D053842:Microsatellite Instability; D044469:Racial Groups
African Americans; Caucasians; Hispanics; MSI; colorectal cancer