Mapping of novel regions of DNA gain and loss by comparative genomic hybridization in esophageal carcinoma in the Black and Colored populations of South Africa

Esophageal cancer (EC) is the leading cause of cancer death in the Black male population in South Africa. Although several oncogenes and tumor suppressor genes have previously been found altered in this cancer, many novel genes remain to be identified. To identify the chromosomal location of these unknown genes, we have analyzed DNA of 29 South African EC patients by comparative genomic hybridization. Frequent loss occurred at chromosome 1p (52%), 4p (52%), 18q (48%), 19p (52%), 19q (55%), and 22q (41%). The most common gains were detected at 1q (41%), 2q (52%), 3q (72%), 5p (31%), 7p (48%), 7q (45%), 8q (55%), and Xq (69%). High level amplification was detected at 2q24-33, 6p21.1-q14, 7p12-q21, 7q11.2-31, 8q22-24, 8q13-qter, 13q21-34, and at 13q32-34. The present comparative genomic hybridization study opens the way for additional targeted studies on these particular chromosomal regions to identify the specific genes involved in the higher susceptibility to specific subtypes of esophageal carcinoma in different geographical regions. The loss of 8p (28%) and Xp (17%) in tumors of male individuals may provide clues to the basis of the sex-biased frequency of occurrence of EC favoring men.