Other Major Projects and Resources
Transplant Cancer Match Study
Cancer risk is substantially elevated among solid organ transplant recipients, who receive long-term immunosuppressant medications to prevent organ rejection. To better understand the etiology of cancer in this population, the Branch is conducting the Transplant Cancer Match Study (http://transplantmatch.cancer.gov/). This study is a collaborative effort with the Health Resources and Services Administration, which oversees the U.S. solid organ transplant network. Data from multiple state and regional cancer registries are linked with the U.S. registry of transplant recipients, to cover approximately 40% of the U.S. transplant population. Strengths of the study include its large size, the availability of detailed data on potential risk factors in transplant recipients (e.g., underlying conditions, viral infections, and medications), and population-based cancer ascertainment.
Immunity and Chimerism
IIB plans to use newly developed, ultra-sensitive technology to detect maternal DNA in neonatal or infant circulation. Analyses will clarify whether mother-to-infant transmission of HIV results from leakage of maternal blood across the placenta and then tolerance of allogeneic cells in the infant. If the results of this pilot study support the hypothesis that chimerism accounts for HIV transmission, during FY2008 this technology would be used to test other hypotheses using previously collected specimens. One, using Jamaican specimens, would examine the possibility that chimerism accounts for breast feeding transmission of HTLV-I. A second, using specimens from South Africa, would examine post-transplant KS tissue for evidence of donor DNA. A third would look for donor DNA in malignancies occurring in Danish transplant recipients identified through linkage of registry data.
Microbiomics and Cancer Risk
Chronic inflammation from infection is related to cancer risk, as demonstrated by H. pylori with gastric cancer and periodontal hygiene with oral and esophageal cancers. There are hundreds and perhaps thousands of currently unidentified, mostly anaerobic bacterial species in the lumen or attached to the epithelium of the colon. New technologies, based on 16s rRNA sequence relationships, can categorize and obtain the relative quantity of all species, known and unknown. IIB is organizing a DCEG working group and in FY2007 will initiate collaborations with genomists and statisticians to assess oligonucleotide-based chip and other technologies. Two or more technologies will be pursued, starting with pilot studies in FY2008 to assess sensitivity, specificity, and reproducibility with various types and conditions of specimens. When deemed satisfactory, probably in FY2008-2009, previously collected specimens from colon and oro-pharyngeal cancer case-control studies will be examined. If these results are promising, in FY2009-2010 collaborations with others holding suitable specimens and data will be established to characterize the relationships of alimentary tract, urinary, and potentially other cancers to the full spectrum of microbial flora.
