Our primary research interests are the study of the genes that are altered in cancer and the cellular pathways these genes perturb. Identifying the genetic alterations and understanding how they work provides the foundation for novel approaches to the prevention, diagnosis and treatment of cancer. ? ? To fulfill these goals, we are using a sequence-based mutational analysis to evaluate genetic alterations in cutaneous malignant melanoma. ? ? Melanoma develops from the malignant transformation of melanocytes. It is the most common fatal skin cancer, and its incidence has increased at a more rapid rate than any other malignancy in the US. Unlike early-stage disease, late stage melanoma has no effective treatment; hence our studies focus on late stage disease. ? ? The clinical progression is assumed to correspond to the accumulation of genetic mutations. In order to develop treatments for advanced disease, it is important to understand the genetic alterations leading to melanoma as such understanding will permit personalized design of treatments for melanoma. ? ? For this project, we have started to establish a tumor bank, which we use as a source of genomic DNA.? In order to determine the quality of the tumor bank a few strategies have been employed: ? a. Cytopatholgy is used to determine the percentage of melanoma cells within the sample provided. Only samples that include at least 75% melanoma-derived cells qualify, to ensure that non-neoplastic cells within the tumors do not complicate the analysis.? b. To verify that we can detect mutations in tumor DNA, we sequence commonly known oncogenic mutations in metastatic melanoma such BRAF and NRAS.? ? Using 40 samples from our tumor bank we have discovered 4 novel mutations in a single gene. As the mutations occur in discreet functional domains and the affected residues within these clusters are highly conserved evolutionarily it is expected that these mutations are functionally important. ? ? These results have been pursued using several avenues: ? a. The discovered mutations were cloned and at least one was found to be activating. More functional assays are being performed to screen the effects of these mutations on tumorigenesis.? b. Another member of the gene pathway was screened for mutations. It was found to harbor both single base mutations in 3 out of 40 cases and to be amplified in 3 out of 40 cases. These results demonstrate that this pathway is a major target for mutational activation in metastatic melanoma as all these alterations occur in a mutually exclusive fashion.? c. More melanoma samples are being screened to attain a more accurate mutation frequency of the discussed genes. ? ? Knowledge that the discovered mutations occur at a mutually exclusive fashion not only increases the frequency of individuals who have mutations in this pathway to 32%, but also provides a strong rationale for development of therapeutic and diagnostic approaches for these individuals. Using these tools, one could envision tailored therapeutics based on the mutations in an individuals cancer.
| Prickett, Todd D; Wei, Xiaomu; Cardenas-Navia, Isabel et al. (2011) Exon capture analysis of G protein-coupled receptors identifies activating mutations in GRM3 in melanoma. Nat Genet 43:1119-26 |
| Rago, Carlo; Huso, David L; Diehl, Frank et al. (2007) Serial assessment of human tumor burdens in mice by the analysis of circulating DNA. Cancer Res 67:9364-70 |
| Huang, Chuan-Hsiang; Mandelker, Diana; Schmidt-Kittler, Oleg et al. (2007) The structure of a human p110alpha/p85alpha complex elucidates the effects of oncogenic PI3Kalpha mutations. Science 318:1744-8 |
