Induction of differentiation and apoptosis in cancer cells through ligands of nuclear hormone receptors (NHRs) is a novel and promising approach to cancer therapy. All-trans-retinoic acid (ATRA), an RA receptor-specific NHR ligand, is now used for selective cancers.

Glioblastoma is the most common and aggressive primary brain cancer. Recent isolation and characterization of brain tumor-initiating cells supports the concept that transformed neural stem cells may seed glioblastoma. We previously identified a wide array of mesenchymal tissue transcripts overexpressed in a broad set of primary glioblastoma (de novo) tumors but not in secondary glioblastoma (derived from lower-grade) tumors, low-grade astrocytomas, or normal brain tissues. Here, we extend this observation and show that a subset of primary glioblastoma tumors and their derived tumor lines express cellular and molecular markers that are associated with mesenchymal stem cells (MSC) and that glioblastoma cell cultures can be induced to differentiate into multiple mesenchymal lineage-like cell types. These findings suggest either that a subset of primary glioblastomas derive from transformed stem cells containing MSC-like properties and retain partial phenotypic aspects of a MSC nature in tumors or that glioblastomas activate a series of genes that result in mesenchymal properties of the cancer cells to effect sustained tumor growth and malignant progression. (Mol Cancer Res 2006;4(9):607 -19)

BackgroundThe programmed death-1/programmed death-ligand-1 (PD-1/PD-L1) immune regulatory axis has emerged as a promising new target for cancer therapeutics, with lasting responses seen in the treatment of metastatic renal and lung carcinomas, as well as melanomas. As tumor surface expression of PD-L1 has been found to correlate with objective responses to anti-PD-L1 immunotherapies, we investigated the expression of PD-L1 in human cervical tumors and provide an adopted scoring system for the systematic evaluation of PD-L1 staining.MethodsImmunohistochemical staining for PD-L1 expression was performed on a tissue microarray of 101 normal and neoplastic cervical tissues. Neoplastic cores were divided into three groups: squamous cell carcinoma, adenosquamous carcinoma, and endocervical adenocarcinoma. PD-L1 expression was scored based on an adopted scoring system accounting to percentage and intensity of positivity, and results provided alongside available clinical and demographic data.ResultsOverall, PD-L1 was positive in 32 of 93 (34.4%) cervical carcinomas. Subcategorically, PD-L1 was positive in 28 of 74 (37.8%) squamous cell carcinomas, two of seven (28.6%) adenosquamous carcinomas, and two of 12 (16.7%) endocervical adenocarcinomas. It was negative in six benign cervical tissues.ConclusionsThis study shows a significant expression of PD-L1 in 34.4% of cervical carcinomas and no expression of PD-L1 in benign cervical tissues. These findings suggest a role for further investigation of anti-PD-L1/PD-1 immunotherapies in the treatment of PD-L1-positive cervical tumors. In addition, our adopted scoring system will facilitate more systematic correlations between tumor reactivity and response to treatment.

We found that high PSCA intensity is significantly associated with adverse prognostic features such as high Gleason score and extra-organ disease. The results of this study suggest that PSCA is a promising tumor marker for the selection of patients at high risk but additional studies are necessary to assess the usefulness of PSCA in patient biopsies.

Overexpression of the Her-2/neu (HER2) oncogene is known to confer important prognostic and predictive value to patients with breast cancer. Controversy exists as to the best method for its determination caused primarily by the variable sensitivities of the different antibodies and interobserver differences, particularly in the group of breast cancers with borderline levels of expression of the protein product. This study was therefore designed to determine the status of the HER2 gene amplification in a group of breast carcinomas with low levels of overexpression. After an initial validation of our procedures, a series of 52 consecutive cases of formalin-fixed, paraffin-embedded breast cancers with low levels of overexpression and a series of 22 cases with no expression by immunohistochemistry were analyzed by fluorescence in situ hybridization (FISH), and the results correlated statistically. Amplification of the HER2 gene was observed in 16% of equivocal to weakly positive cases. Those that were amplified showed low levels of amplification with ratios less than 4.5 and a characteristic scattered pattern of distribution of HER2 signals in the FISH assay. In addition, heterogeneity was noted in two cases in the amplification of the HER2 gene within the same tumor samples with pockets of amplified tumor cells amidst nonamplified tumor cells. In cases without amplification, a statistically significant number showed chromosome 17 polysomy. In conclusion, equivocal to low levels of HER2 overexpression in breast cancers are associated, in the majority of cases, with chromosome 17 polysomy and a corresponding increase in the HER2 gene numbers. True gene amplification is present in only a minority of cases. FISH analysis should be used for confirmation of gene amplification. Prior screening and selection of appropriate immunohistochemistry-positive areas for FISH analysis may prove beneficial.

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We report a case of a virilized 59-yr-old woman with elevated serum testosterone levels and bilateral macronodular adrenal hyperplasia. The patient underwent laparoscopic right adrenalectomy, after which the elevated testosterone level transiently normalized. The immediate postoperative depression of the testosterone level suggested that the process was driven by gonadotropins that were suppressed by the stress of surgery. The excised right adrenal mass contained testosterone by immunohistochemistry and LH receptor mRNA by in situ hybridization. The recurrence of hyperandrogenemia suggested that the enlarged left adrenal was also secreting testosterone. The serum testosterone level increased in response to im injection of human chorionic gonadotropin, suggesting control by aberrant LH receptors. Injection of leuprolide acetate (7.5 mg im) to suppress LH levels resulted in normalization of the testosterone level 12 d later that persisted for several weeks. Ectopic receptors mediating Cushing's syndrome have been described in several cases of bilateral adrenal hyperplasia and adrenal adenoma. This is the first case to our knowledge in which pure androgen overproduction in adrenal hyperplasia has been shown to be controlled by LH receptors. In our patient, the control of androgen secretion by LH may explain the postmenopausal onset of virilization and the transient postoperative normalization of the serum testosterone level.

Endometrial adenocarcinoma is the most common gynecologic malignancy in the United States. However, reliable diagnostic or prognostic tumor markers have not been identified for endometrial cancer. In this study, we examined whether urokinase plasminogen activator receptor (UPAR), a glycosyl-phosphatidylinositol-linked membrane protein, is a candidate diagnostic or prognostic marker for patients with cancer of the endometrium. Sixty-five surgically excised, formalin-fixed endometrial tissue specimens were accessioned through the Department of Pathology Registry at the University of California, Los Angeles, and analyzed for UPAR expression by using immunohistochemical techniques. A retrospective review was also performed to determine stage and histopathologic grade of disease, recurrence, and mortality. No expression of UPAR protein was present in seven patients with benign neoplasia of the endometrium. UPAR protein expression highly correlated with stage of disease (ungrouped Spearman correlation = 0.625, P < 0.0001): 40% of patients with stage I, 66% of patients with stage II, 100% of patients with stage III, and 85% with stage IV demonstrated the highest level of UPAR expression. Moreover, high UPAR expression positively correlated with grade of disease (ungrouped Spearman correlation = 0.71, P < 0.0001): 29% of grade 1 specimens, 57% of grade 2, and over 90% of specimens with grade 3, the majority representing uterine papillary serous carcinoma and mixed malignant mesodermal tumor. Finally, UPAR protein expression also positively correlated with rate of recurrence and mortality in patients with adenocarcinoma of the endometrium (ungrouped P = 0.034). Our data suggest that UPAR is a useful prognostic marker for biologically aggressive forms of endometrial cancer