Frequent mutation of the E2F-4 cell cycle gene in primary human gastrointestinal tumors

  • Rhonda F. Souza
  • , Jing Yin
  • , Kara N. Smolinski
  • , Tong Tong Zou
  • , Suna Wang
  • , Ying Qiang Shi
  • , Mun Gan Rhyu
  • , John Cottrell
  • , John M. Abraham
  • , Kelli Biden
  • , Lisa Simms
  • , Barbara Leggett
  • , G. Steven Bova
  • , Tom Frank
  • , Steven M. Powell
  • , Haruhiko Sugimura
  • , Joanne Young
  • , Noam Harpaz
  • , Kenji Shimizu
  • , Nagahide Matsubara
  • Stephen J. Meltzer

Research output: Contribution to journalArticlepeer-review

117 Scopus citations

Abstract

The E2F group of transcription factors transactivates genes that promote progression through the G1-S transition of the cell cycle. Members of the retinoblastoma (Rb) family of proteins bind to E2Fs and inhibit this function. E2F-4, one example of the E2F group, function as an oncogene when transfected into nontransformed cells in vitro. On the other hand, mice that are homozygously lacking a normal E2F-1 gene develop cancers, consistent with a tumor-suppressive role for this gene. The exact function of E2Fs has thus been unclear; moreover, direct involvement of this gene in primary human tumorigenesis has not been shown. We, therefore, investigated mutation within the E2F-4 coding region in 16 primary gastric adenocarcinomas, 12 ulcerative colitis-associated neoplasms, 46 sporadic colorectal carcinomas, 9 endometrial cancers, and 3 prostatic carcinomas. We limited our investigation to the serine repeat within E2F-4, reasoning that this tract might be altered in genetically unstable tumors (replication error-positive, or RER+). All tumors were RER+, with the exception of a control group of 15 RER - sporadic colorectal carcinomas. PCR with incorporation of [32P]dCTP was performed using primers flanking the serine trinucleotide (AGC) repeat. Twenty-two of 59 gastrointestinal tumors (37%) contained E2F-4 mutations; these comprised 5 of 16 gastric tumors (31%), 4 of 12 ulcerative colitis-associated neoplasms (33%, including 1 dysplastic lesion), and 13 of 31 sporadic colorectal cancers (42%). No mutation was present in any of the endometrial, prostate, or RER- colorectal tumors. Of note, homozygous mutations occurred in three cases, and two of seven informative patients showed loss of one E2F-4 allele in their tumors. Furthermore, the RER+ sporadic colorectal tumors were evaluated at trinucleotide repeats within the genes for N-cadherin and B- catenin; no tumors demonstrated mutation of these genes. These data suggest that E2F-4 is a target of defective DNA repair in these tumors.

Original languageEnglish
Pages (from-to)2350-2353
Number of pages4
JournalCancer Research
Volume57
Issue number12
StatePublished - 15 Jun 1997
Externally publishedYes

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