Faculty Bibliography

Carney complex is a syndrome that may include cardiac and mucocutaneous myxomas, spotting skin pigmentation, and endocrine lesions. Many patients with Carney complex have been shown to have a stop codon mutation in the PRKAR1A gene in the 17q22-24 region. Here we present the case of a 57 year-old man with multiple skin lesions and cardiac myxomas. Histology of the skin lesions showed lentigenous melanocytic hyperplasia and cutaneous myxomas, confirming the diagnosis of Carney complex. Lesional and control normal tissue from the patient were identified and sequenced for the PRKAR1A gene. A germline missense mutation was identified at exon 1A. This is the first report of this mutation, and one of the few reported missense mutation associated with Carney complex. This finding strengthens the argument that there are alternative ways in which the protein kinase A 1-alpha subunit plays a role in tumorigenesis

ABSTRACT: BACKGROUND: The goal of our study was to investigate the molecular underpinnings associated with the relatively aggressive clinical behavior of prostate cancer (PCa) in African American (AA) compared to Caucasian American (CA) patients using a genome-wide approach. METHODS: AA and CA patients treated with radical prostatectomy (RP) were frequency matched for age at RP, Gleason grade, and tumor stage. Array-CGH (BAC SpectralChip2600) was used to identify genomic regions with significantly different DNA copy number between the groups. Gene expression profiling of the same set of tumors was also evaluated using Affymetrix HG-U133 Plus 2.0 arrays. Concordance between copy number alteration and gene expression was examined. A second aCGH analysis was performed in a larger validation cohort using an oligo-based platform (Agilent 244K). RESULTS: BAC-based array identified 27 chromosomal regions with significantly different copy number changes between the AA and CA tumors in the first cohort (Fisher's exact test, P < 0.05). Copy number alterations in these 27 regions were also significantly associated with gene expression changes. aCGH performed in a larger, independent cohort of AA and CA tumors validated 4 of the 27 (15%) most significantly altered regions from the initial analysis (3q26, 5p15-p14, 14q32, and 16p11). Functional annotation of overlapping genes within the 4 validated regions of AA/CA DNA copy number changes revealed significant enrichment of genes related to immune response. CONCLUSIONS: Our data reveal molecular alterations at the level of gene expression and DNA copy number that are specific to African American and Caucasian prostate cancer and may be related to underlying differences in immune response

Hepatocellular carcinoma (HCC) is the sixth most common malignancy and the third leading cause of cancer deaths worldwide. Proper classification and early identification of HCC and precursor lesions is essential to the successful treatment and survival of HCC patients. Recent molecular genetic, pathologic, and clinical data have led to the stratification of hepatic adenomas into three subgroups: those with mutant TCF1/HNF1 alpha gene, those with mutant beta-catenin, and those without mutations in either of these loci. Hepatic adenomas with alpha-catenin mutations have a significantly greater risk for malignant transformation in comparison with the other two subgroups. Telangiectatic focal nodular hyperplasia has now been reclassified as telangiectatic adenoma due to the presence of non-random methylation patterns, consistent with the monoclonal origin which is similar to hepatic adenoma and HCC. HCC precursor lesions demonstrate unique molecular alterations of HSP70, CAP2, glypican 3, and glutamine synthetase that have proven useful in the histologic diagnosis of early HCC. Though specific genetic alterations depend on HCC etiology, the main proteins affected include cell membrane receptors (in particular tyrosine kinase receptors) as well as proteins involved in cell signaling (specifically Wnt/beta-catenin, Ras/Raf/MEK/ERK and PI3K/Akt/mTOR pathways), cell cycle regulation (i.e. p53, p16/INK4, cyclin/cdk complex), invasiveness (EMT, TGF-beta) and DNA metabolism. Advances in gene expression profiling have provided new insights into the molecular genetics of HCC. HCCs can now be stratified into two clinically relevant groups: Class A, the low survival subclass (overall survival time 30.3+/- 8.02 months), shows strong expression signatures of cell proliferation and antiapoptosis genes (such as PNCA and cell cycle regulators CDK4, CCNB1, CCNA2, and CKS2) as well as genes involving ubiquitination and sumoylation; Class B, the high survival subclass (overall survival time 83.7 +/-10.3 months), does not have the above expression signature. In fact, insights into HCC-specific alterations of signal transduction pathways and protein expression patterns have led to the development of new therapeutic agents with molecular targets such as EGFR, VEGF, or other multi-kinase inhibitors. In the future, these specific molecular alterations in HCC can potentially serve as diagnostic tools, prognostic markers, and/or therapeutic targets with the potential to alter clinical outcomes

Hormones and their receptors play an important role in the development and progression of breast carcinoma. Although the primary focus has been on oestrogen and oestrogen receptor (ER), androgen, androgen receptor (AR) and its coactivator(s) have been implicated in tumorigenesis of breast carcinoma and warrant further investigation. AR coactivator p44/Mep50 is identified as a subunit of methylosome complex and lately characterized as an AR coactivator that enhances AR mediated transcription activity in a ligand dependent manner. In prostate cancer, p44 is expressed in the nucleus of benign epithelia and translocated into the cytoplasm in cancer cells. Furthermore, nuclear expression of p44 inhibits prostate cancer growth. In this report, we examined the expression and function of p44 in breast cancer. In addition to being an AR coactivator, p44 also functions as an ER coactivator. In contrast to findings in prostate cancer, the expression of p44 shows strong cytoplasmic expression in morphologically normal terminal ductal lobular units, while nuclear p44 is observed in both ductal carcinoma in situ and invasive carcinoma. Further, overexpression of nuclear-localized p44 stimulates proliferation and invasion in MCF7 breast cancer cells in the presence of oestrogen and the process is ERalpha dependent. These findings strongly suggest that p44 plays a role in mediating the effects of hormones during tumorigenesis in breast

A major obstacle in treating prostate cancer is the development of androgen-independent disease. In this study, we examined LEF1 expression in androgen-independent cancer as well as its regulation of androgen receptor (AR) expression, prostate cancer growth, and invasion in androgen-independent prostate cancer cells. Affymetrix microarray analysis of LNCaP and LNCaP-AI (androgen-independent variant LNCaP) cells revealed 100-fold increases in LEF1 expression in LNCaP-AI cells. We showed that LEF1 overexpression in LNCaP cells resulted in increased AR expression and consequently enhanced growth and invasion ability, whereas LEF1 knockdown in LNCaP-AI cells decreased AR expression and, subsequently, growth and invasion capacity. Chromatin immunoprecipitation, gel shift, and luciferase assays confirmed LEF1 occupancy and regulation of the AR promoter. Thus, we identified LEF1 as a potential marker for androgen-independent disease and as a key regulator of AR expression and prostate cancer growth and invasion. LEF1 is highly expressed in androgen-independent prostate cancer, potentially serving as a marker for androgen-independent disease

PURPOSE: The tumor microenvironment significantly influences prostate cancer progression. Androgen receptor exerts its effect through downstream target genes to regulate prostate cancer cell proliferation. The c-FLIP gene was recently shown to be an androgen receptor target gene. c-FLIP is an inactive homologue of caspase-8 and, thus, it inhibits the death receptor mediated apoptosis pathway. c-FLIP over expression was shown to accelerate the progression of prostate cancer cells to androgen independence. We evaluated the role of c-FLIP expression in stromal cells in prostate cancer development. MATERIALS AND METHODS: We examined c-FLIP expression in 53 androgen dependent and 21 androgen independent prostate cancer stromal cells by immunohistochemical analysis. The effects of c-FLIP over expression in stromal cells on the growth and invasion of LNCaP and PC3 prostate cancer cells were determined in indirect coculture systems. RESULTS: At the androgen dependent stage the stromal c-FLIP level was increased in prostate cancer tissue. The expression level of stromal c-FLIP was associated with tumor differentiation. However, stromal c-FLIP expression was not increased in androgen independent human prostate cancer. c-FLIP over expression in stromal cells stimulated the growth and invasion of prostate cancer, including LNCaP and PC3 cells in vitro. CONCLUSIONS: These results indicate the over expression of stromal c-FLIP and its function for promoting prostate cancer growth and invasion

MDM2 is a key negative regulator of tumor suppressor p53. A single nucleotide polymorphism in the MDM2 promoter, SNP309, enhances transcriptional activation of MDM2 and has been associated with early onset of several types of cancer. In this study, we attempted to determine if the MDM2 SNP309 polymorphism plays a role in the aggressive phenotype seen in African American (AA) prostate cancer by examining the association between MDM2 SNP309 and MDM2 protein levels in prostate cancer (PCa) patients of different racial backgrounds. Prospectively enrolled PCa patients (AA=51, CA=50) were evaluated for MDM2 SNP309 and MDM2 protein expression. MDM2 overexpression, defined as >10% of tumor cells in three tissue cores, was assessed using immunohistochemistry on tissue microarray. MDM2 protein expression was significantly greater in CA than AA patients (78% versus 45% respectively, p=0.0007). Germline DNA was analyzed by PCR-RFLP then confirmed by DNA sequencing. MDM2 SNP309 genotype frequencies did not differ significantly between AA and CA PCa patients (AA: TT 68.6%, TG 25.5%, GG 5.9%; CA: TT 62.0%, TG 20.0%, GG 18.0%; p=0.16), suggesting that the MDM2 SNP309 allele does not play a significant role in the observed overexpression