Normal prostate epithelial cells are dependent on androgen for growth, differentiation and survival. A subset of prostate tumors is similarly dependent on androgen, and androgen ablation therapy typically results in the stasis or regression of these tumors. However, hormone-independent clones commonly arise following androgen ablation, and these clones typically display a more aggressive, less differentiated phenotype. Hormone-independent tumors retain androgen receptor (AR) expression. This observation suggests that these tumors may still require AR signaling, although in an androgen-independent manner. This hypothesis is supported by the observation that serum prostate-specific antigen levels increase in hormone-independent cancer despite the absence of androgen. We propose that additional AR targets are necessary for mediating tumor progression, in both hormonedependent and-independent states. We have stimulated androgen-responsive LAPC4 cells with androgens, and we have used microarrays to identify additional androgen targets. These targets include transcription factors, growth factors, signaling molecules and cytoskeletal and metabolic proteins. The in vivo androgen dependence of these targets has been confirmed in xenograft models. We are now using laser capture microdissection and the polymerase chain reaction with reverse transcription (Taqman) to quantify target gene expression in benign and malignant prostate epithelia from multiple patients. We are clustering tumor samples based on their AR target gene expression profiles in order to identify subsets of genes that are misexpressed in tumors relative to benign tissues, are expressed in androgen-independent tumors and correlate with biochemical failure of radical prostatectomy (as determined by rising prostate-specific antigen levels after surgery).

No abstract

Epithelioid glioblastoma (eGBM) and pleomorphic xanthoastrocytoma (PXA) with anaplastically transformed foci (ePXA) show overlapping features. Eleven eGBMs and 5 ePXAs were reviewed and studied immunohistochemically. Fluorescence in situ hybridization for EGFR amplification, PTEN deletion and ODZ3 deletion was also performed, with Ilumina 450 methylome analysis obtained in five cases. The average age for eGBM was 30.9 (range 2-79) years, including five pediatric cases and a M : F ratio of 4.5. The ePXA patients had a M : F ratio of 4 and averaged 21.2 (range 10-38) years in age, including two pediatric cases. Six eGBMs and two ePXAs recurred (median recurrence interval of 12 and 3.3 months, respectively). All tumors were composed of solid sheets of loosely cohesive, "melanoma-like" cells with only limited infiltration. ePXAs showed lower grade foci with classic features of PXA. Both tumor types showed focal expression of epithelial and glial markers, retained INI1 and BRG1 expression, occasional CD34 positivity, and lack of mutant IDH1 (R132H) immunoreactivity. BRAF V600E mutation was present in four eGBMs and four ePXAs. ODZ3 deletion was detected in seven eGBMs and two ePXAs. EGFR amplification was absent. Methylome analysis showed that one ePXA and one eGBM clustered with PXAs, one eGBM clustered with low-grade gliomas, and two eGBMs clustered with pediatric-type glioblastomas. Common histologic, immunohistochemical, molecular and clinical features found in eGBM and ePXA suggest that they are closely related or the same entity. If the latter is true, the nomenclature and WHO grading remains to be resolved.

The INI1/SMARCB1 protein product (INI1), a component of a transcription complex, was recently implicated in the pathogenesis of schwannomas in two members of a single family with familial schwannomatosis 1 . Tumors were found to have both constitutional and somatic mutations of the SMARCB1 gene and showed a mosaic pattern of loss of INI1 expression by immunohistochemistry, suggesting a tumor composition of mixed null and haploinsufficient cells. To determine if this finding could be extended to all tumors arising in familial schwannomatosis, and how it compares to other multiple schwannoma syndromes (sporadic schwannomatosis and neurofibromatosis 2) as well as to sporadic, solitary schwannomas, we performed an immunohistochemistry analysis on 45 schwannomas from patients with multiple schwannoma syndromes and on 38 solitary, sporadic schwannomas from non-syndromic patients. A mosaic pattern of INI1 expression was seen in 93% of tumors from familial schwannomatosis patients, 55% of tumors from sporadic schwannomatosis, 83% of NF2-associated tumors and only 5% of solitary, sporadic schwannomas. These results confirm a role for INI1/SMARCB1 in multiple schwannoma syndromes and suggest that a different pathway of tumorigenesis occurs in solitary, sporadic tumors.The SMARCB1 (also known as INI1, hSNF5 and BAF47) is a tumor suppressor gene that maps to chromosome band 22q11.2. Biallelic inactivation of SMARCB1 is frequent in atypical teratoid/rhabdoid tumors (AT/RT) and malignant rhabdoid tumors, aggressive malignant tumors of the central nervous system and kidneys in children. Constitutional mutations of SMARCB1 can be seen in rare familial cases of AT/RT 2 . The protein encoded by SMARCB, the INI1 protein, is a subunit of the SWI/SNF ATP-dependent chromatin-remodeling complex and is ubiquitously expressed in all cell types examined 3 . AT/RT occurring both sporadically SMARCB1 lies in the candidate region for familial schwannomatosis, a form of neurofibromatosis characterized by multiple schwannomas without vestibular nerve involvement 5,6 . In a recent report 1 , constitutional and somatic mutations of the SMARCB1gene were found in tumors from a single kindred with familial schwannomatosis. Loss of nuclear INI1 protein expression by immunohistochemistry was seen in four separate tumors from two members of this family. However, in contrast to the immunostaining pattern of INI1 in AT/ RT, loss of INI1 expression was seen in only a subset of tumor cells suggesting a mosaic makeup of null and haploinsufficent cells. Furthermore, several previous studies have identified somatically acquired mutations in the NF2 gene in schwannomatosis tumors 6 ,, 7 , but in tumors from this family no molecular evidence of NF2 involvement was seen, raising the question of how representative this family may be. Here we report an expansion of these results to other familial schwannomatosis kindreds as well as analysis of the INI expression pattern in tumors associated with other multiple schwannoma syndromes (sporadic schwannomatos...

Glioblastoma multiforme is a highly malignant and aggressive primary brain tumor with a dismal prognosis. We studied the association of immunohistochemical expression of hypoxia inducible factor-1 alpha (HIF-1α), telomerase reverse transcriptase (TERT), isocitrate dehydrogenase 1 (IDH1) and tumor protein p53 with overall survival (OS) in glioblastoma patients uniformly treated by standard of care, with adequate follow-up. In 87 patient samples studied, 59 were male and 28 were female. The median age was 55 years. The median follow-up was 27.7 months and the median overall survival was 14.9 months. Nuclear staining of HIF-1α was expressed in all samples and scored as strong in 42 (48%) and weak in 45 (52%). Multivariable Cox regression revealed strong HIF-1α expression as an independent poor prognostic factor (Hazard Ratio 2.12, 95% CI 1.20 -3.74, P = 0.01). There was a statistically significant difference in OS (9.8 months vs. 16.3 months) between the "HIF-1α -strong and TERT -strong" and the "HIF-1α -weak and TERT -weak" patient subgroups, as evaluated by Kaplan-Meier analysis (P = 0.005). In our study, HIF-1α expression was an independent predictor of OS. The subgroup of patients with strong expression of both HIF-1α and TERT had the poorest prognosis.