Faculty Bibliography

BACKGROUND: Function of the retinoblastoma tumor suppressor protein (pRB) may be compromised at a genetic level by gene loss or mutation or at a post-translational level by hyperphosphorylation. In this study, we examined adult soft tissue sarcomas (ASTS) to determine if alterations of pRB were associated with distinct patterns of pRB expression and clinical outcome. DESIGN: We investigated 86 ASTS patients using monoclonal antibodies that distinguish between hyperphosphorylated and underphosphorylated pRB products. We also used microsatellite analysis to investigate the genetic status of the RB locus. We correlated pRB alterations with proliferative activity, and with clinicopathological outcomes. RESULTS: Altered patterns of pRB expression are common in ASTS occurring in 84% of cases, and it is significantly associated with proliferative activity (p<0.001). Patients whose tumors either lack expression of pRB, or express hyperphosphorylated forms of pRB, have poor survivals compared to patients whose tumors exhibit a normal, underphosphorylated pattern of pRB expression (p=0.03). In addition, 63% of cases lacking expression of pRB showed loss-of-heterozygosity at the locus. CONCLUSIONS: Inactivation of pRB is common in adult STS, which may be due to either gene loss or post-translational modification, namely hyper-phosphorylation. Both mechanisms are associated with tumor cell proliferation and poor survival

PURPOSE: Recent data indicate that cDNA microarray gene expression profile of blood cells can reflect disease states and thus have diagnostic value. We tested the hypothesis that blood cell gene expression can differentiate between bladder cancer and other genitourinary cancers as well as between bladder cancer and healthy controls. EXPERIMENTAL DESIGN: We used Affymetrix U133 Plus 2.0 GeneChip (Affymetrix, Santa Clara, CA) to profile circulating blood total RNA from 35 patients diagnosed with one of three types of genitourinary cancer [bladder cancer (n = 16), testicular cancer (n = 10), and renal cell carcinoma (n = 9)] and compared their cDNA profiles with those of 10 healthy subjects. We then verified the expression levels of selected genes from the Affymetrix results in a larger number of bladder cancer patients (n = 40) and healthy controls (n = 27). RESULTS: Blood gene expression profiles distinguished bladder cancer patients from healthy controls and from testicular and renal cancer patients. Differential expression of a combined set of seven gene transcripts (insulin-like growth factor-binding protein 7, sorting nexin 16, chondroitin sulfate proteoglycan 6, and cathepsin D, chromodomain helicase DNA-binding protein 2, nell-like 2, and tumor necrosis factor receptor superfamily member 7) was able to discriminate bladder cancer from control samples with a sensitivity of 83% (95% confidence interval, 67-93%) and a specificity of 93% (95% confidence interval, 76-99%). CONCLUSION: We have shown that the gene expression profile of circulating blood cells can distinguish bladder cancer from other types of genitourinary cancer and healthy controls and can be used to identify novel blood markers for bladder cancer

The kinase pathway comprising RAS, RAF, mitogen-activated protein kinase kinase (MEK) and extracellular signal regulated kinase (ERK) is activated in most human tumours, often through gain-of-function mutations of RAS and RAF family members. Using small-molecule inhibitors of MEK and an integrated genetic and pharmacologic analysis, we find that mutation of BRAF is associated with enhanced and selective sensitivity to MEK inhibition when compared to either 'wild-type' cells or cells harbouring a RAS mutation. This MEK dependency was observed in BRAF mutant cells regardless of tissue lineage, and correlated with both downregulation of cyclin D1 protein expression and the induction of G1 arrest. Pharmacological MEK inhibition completely abrogated tumour growth in BRAF mutant xenografts, whereas RAS mutant tumours were only partially inhibited. These data suggest an exquisite dependency on MEK activity in BRAF mutant tumours, and offer a rational therapeutic strategy for this genetically defined tumour subtype

OBJECTIVES: We have previously reported on the disparity in the clinicopathologic features of prostate cancer between black and white patients at our equal-access institution during the 1990s. The goal of this study was to determine whether the worse clinicopathologic features of prostate cancer in black patients have persisted in the 2000s. METHODS: We examined 362 men (224 black and 138 white) treated with radical prostatectomy at the Veterans Affairs Medical Center in New York. We compared the clinicopathologic variables between 227 patients treated during the 1990s (group 1) and 135 treated in the 2000s (group 2). RESULTS: In group 1, black patients were significantly younger (P < 0.001) and had a greater prostate-specific antigen (PSA) level (P = 0.001), Gleason score (P = 0.005), and stage (P = 0.03) than white patients. In group 2, black patients continued to have significantly greater PSA levels (P = 0.04) and Gleason scores (P = 0.005) than white patients. Comparing only the black patients, those in group 2 had significantly lower PSA levels (P < 0.001) and stage (P = 0.03), but had worse Gleason scores (P = 0.03) than those in group 1. On multivariate analysis, black patients were significantly more likely to have a worse Gleason score (P = 0.005) than white patients. CONCLUSIONS: Our data have demonstrated a narrowing of the differences in pathologic stage between black and white patients in the 2000s. However, black men have continued to have worse Gleason scores and greater PSA levels than white patients. These findings suggest that there may be different patterns of molecular alterations in black men that may contribute to the poor tumor differentiation. Additional research is underway to better characterize these underlying molecular mechanisms