Recently several low-grade renal cell tumors, distinct from those recognized by the 2004 World Health Organization classification of renal tumors, have been described. These tumors had similar clinicopathologic features, being low-stage tumors with cystic, tubuloacinar, and/or papillary architecture. The tumor cells were low grade with variable amounts of clear cytoplasm that was positive for cytokeratin 7 (CK7), but negative for CD10. Genetic changes characteristic of clear cell or papillary renal cell carcinoma were not seen in these tumors. We investigated the morphologic, immunohistochemical, and genetic features of 36 additional tumors. Immunohistochemistry was carried out for CK7, carbonic anhydrase 9, α-methylacyl-CoA racemase, CD10, TFE-3, and desmin. Interphase fluorescence in situ hybridization was carried out with centromeric probes for chromosomes 3, 7, 17, and a subtelomeric probe for 3p25. Sequencing of von Hippel-Lindau gene and analysis of the methylation status of the promoter region was also carried out in 2 tumors. Thirty-six tumors from 33 patients (mean age: 60.4 , range: 26 to 88; 17 men and 16 women) were studied. Three patients had bilateral tumors and 1 patient had von Hippel-Lindau disease. Follow-up was available in 60% (20/33) of the patients for a mean of 27.4 (range 1 to 85) months. No patient had evidence of the disease after surgery except for the patient with von Hippel-Lindau disease, who was alive with stable disease in the contralateral kidney. All 36 tumors were small (mean size 2.4 cm; range 0.9 to 4.5 cm) and low stage (pT1). The majority was cystic and had prominent fibrous capsule and stroma. The tumors were composed of variable amount of cysts, papillae, tubules, acini, and solid nests. The most characteristic histologic features were branching tubules and acini and anastomosing clear cell ribbons with low-grade nuclei. All tumors were strongly positive for CK7 and variably positive for CA9, but largely negative for CD10, and negative for α-methylacyl-CoA racemase and TFE-3. All but 1 tumor had no gains of chromosomes 7 and 17 and deletion of 3p. Only 1 tumor had low copy number gains of chromosomes 7 and 17. VHL gene mutation and promoter methylation were negative in 2 tumors analyzed. We show that these tumors, which we term as "clear cell tubulopapillary renal cell carcinoma," constitute a unique subtype in the spectrum of renal epithelial neoplasia based on their characteristic morphologic and immunohistochemical features.

To our knowledge this is the largest analysis investigating the impact of VHL inactivation on the outcome of vascular endothelial growth factor targeted agents in metastatic renal cell carcinoma. We did not find a statistically significant increase in response to vascular endothelial growth factor targeted agents in patients with VHL inactivation. Loss of function mutations identified a population of patients with a greater response. Investigation of downstream markers is under way.

PURPOSE Biomarkers that predict response or toxicity to antiangiogenic therapy are sought to favorably inform the risk/benefit ratio. This study evaluated the association of vascular endothelial growth factor (VEGF) and VEGF receptor 2 (VEGFR2) genetic polymorphisms with the development of hypertension (HTN) and clinical outcome in meta-static clear cell renal cell carcinoma (MCCRCC) patients treated with sunitinib. PATIENT AND METHODS Sixty-three MCCRCC patients receiving sunitinib (50 mg 4/2) with available blood pressure (BP) data and germline DNA were retrospectively identified. A panel of candidate VEGF and VEGFR2 single nucleotide polymorphisms (SNPs) were evaluated for associations with the development of hypertension and clinical outcome. RESULTS VEGF SNP −634 genotype was associated with the prevalence and duration of sunitinib-induced hypertension (as defined by systolic pressure ≥150 mmHg and/or diastolic pressure ≥90 mmHg) in both univariable analysis (P = .03 and .01, respectively) and multivariable analysis, which adjusted for baseline BP and use of antihypertension medication (P = .05 and .02, respectively). Patients with the GG genotype were estimated to have a greater likelihood of being hypertensive during treatment compared with patients with the CC genotype (odds ratio of 13.62, 95% confidence interval [CI] 3.71–50.04). No single VEGF or VEGFR SNPs were found to correlate with clinical outcome. However, the combination of VEGF SNP 936 and VEGFR2 SNP 889 were associated with overall survival after adjustment for prognostic risk group (P = .03). CONCLUSIONS In MCCRCC patients treated with sunitinib, VEGF SNP −634 is associated with hypertension and a combination of VEGF SNP 936 and VEGFR2 SNP 889 genotypes is associated with overall survival.

None of the tumours of BRCA1 mutation carriers showed CCND1 amplification and only one tumour showed HER2 amplification. In contrast, a large proportion of cyclin D1 and HER2 overexpression in tumours of non-familial breast cancer cases could be accounted for by amplification of these genes. These data suggest that breast tumorigenesis in BRCA1 mutation carriers occurs by a molecular mechanism distinct from that of age matched non-familial cases.

Angiogenesis is central to the growth of normal tissues and tumors. Inhibiting this pathway has been a strategy for drug development for tumors not responsive to most agents used in chemotherapy. Notably, signaling mediated by vascular endothelial growth factor (VEGF) is a key target because aberrant signaling via this pathway is frequently associated with neoangiogenesis in tumors. The drug-discovery effort to blunt VEGF signaling has led to the approval of bevacizumab and several receptor tyrosine kinase inhibitors (TKIs) that have shown efficacy in the clinical management of breast, colorectal, lung, and kidney cancer. Understanding the genetic variability in VEGF and VEGF receptor has led to identifying genotypic variations (single nucleotide polymorphisms [SNPs]) associated with treatment outcome and toxicity. Notably, identification of SNPs in VEGF associated with angiogenesis inhibitor treatment-induced hypertension and outcome provides exciting opportunities for personalized medicine to improve outcome and reduced toxicity with these novel TKIs.

A distinctive feature of BRCA1-linked breast cancers is that they typically do not express estrogen receptor-a (ERa). Previous investigation suggests that methylation of CpGs within the ERa promoter mediates repression of gene expression in some ERa-negative breast cancers. To determine if methylation of CpGs within the ERa promoter is associated with BRCA1-linked breast cancers, we evaluated methylation in exon 1 of the ERa gene in 40 ERa-negative breast cancers, 20 of which were non BRCA1-linked and 20 BRCA1-linked. CpG methylation was evaluated by either methylationsensitive restriction digest (HpaII), methylation-sensitive PCR (MSP), or direct sequencing of bisulfite-treated genomic DNA. Results from HpaII digests and MSP documented a high degree of methylation, the MSP data showing slightly higher methylation in the BRCA1-linked group. CpGs analysed by direct sequencing showed an overall average methylation of 25% among non BRCA1-linked cancers and 40% among BRCA1-linked cancers (P=0.0031). The most notable difference was found at five particular CpGs, each of which exhibited a greater than twofold increase in methylation in the BRCA1-linked group compared to the non BRCA1-linked group (P50.03 for each CpG). Methylation of certain critical CpGs may represent an important factor in transcriptional repression of the ERa gene in BRCA1-linked breast cancers.

Proteasome inhibition following DNA damage results in the synergistic induction of apoptosis via a nuclear factor-KBindependent mechanism. In this study, we identify the role of p53 in mediating apoptosis by the sequence-specific treatment involving the DNA-damaging, topoisomerase I -targeting drug SN-38 followed by the proteasome inhibitor PS-341 (SN-38!PS-341). The p53-dependent sensitization of DNA damage -induced apoptosis by PS-341 is accompanied by persistent inhibition of proteasome activity and increased cytosolic accumulation of p53, including higher molecular weight forms likely representing ubiquitinated species. In contrast, pretreatment with PS-341 followed by treatment with SN-38 (PS-341!SN-38), which leads to an antagonistic interaction, results in transient inhibition of proteasome activity and accumulation of significantly lower levels of p53 localized primarily to the nucleus. Whereas cells treated with PS-341!SN-38 undergo G 2 + M cell cycle arrest, cells treated with SN-38!PS-341 exhibit a decreased G 2 + M block with a concomitant increase in the sub-G 1 population. Decreased accumulation of cells in the G 2 + M phase of the cell cycle in SN-38!PS-341 -treated cells compared with PS-341!SN-38 -treated cells correlates with enhanced apoptosis and reduced expression of two p53-modulated proteins, 14-3-3S and survivin, both of which play critical roles in regulating G 2 + M progression and apoptosis. The functional role of 14-3-3S or survivin in regulating the divergent function of p53 in response to SN-38!PS-341 and PS-341!SN-38 treatment in inducing apoptosis versus G 2 + M arrest/DNA repair, respectively, was confirmed by targeted down-regulation of these proteins. These results provide insights into the mechanisms by which inhibition of proteasome activity modulates DNA damage-induced apoptosis via a p53-dependent pathway. [Mol Cancer Ther 2005;4(12):1880 -90]

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