Cyclin-dependent kinase 5 (Cdk5) is a small serine/threonine kinase that plays a pivotal role during development of the CNS. Cables, a novel protein, interacts with Cdk5 in brain lysates. Cables also binds to and is a substrate of the c-Abl tyrosine kinase. Active c-Abl kinase leads to Cdk5 tyrosine phosphorylation, and this phosphorylation is enhanced by Cables. Phosphorylation of Cdk5 by c-Abl occurs on tyrosine 15 (Y15), which is stimulatory for p35/Cdk5 kinase activity. Expression of antisense Cables in primary cortical neurons inhibited neurite outgrowth. Furthermore, expression of active Abl resulted in lengthening of neurites. The data provide evidence for a Cables-mediated interplay between the Cdk5 and c-Abl signaling pathways in the developing nervous system.
Renal cell carcinoma (RCC) occurs in 2-4% of patients with tuberous sclerosis complex (TSC). Previous reports have noted a variety of histologic appearances in these cancers, but the full spectrum of morphologic and molecular features has not been fully elucidated. We encountered 46 renal epithelial neoplasms from 19 TSC patients and analyzed their clinical, pathological and molecular features, enabling separation of these 46 tumors into three groups. The largest subset of tumors (n=24) had a distinct morphological, immunological and molecular profile, including prominent papillary architecture and uniformly deficient SDHB expression prompting the novel term “TSC-associated papillary RCC.” The second group (n=15) was morphologically similar to a hybrid oncocytic/chromophobe tumor (HOCT) while the last 7 renal epithelial neoplasms of group 3 remained unclassifiable. The TSC-associated papillary RCCs (PRCC) had prominent papillary architecture lined by clear cells with delicate eosinophilic cytoplasmic thread-like strands that occasionally appeared more prominent and aggregated to form eosinophilic globules. All 24 (100%) of these tumors were the International Society of Urological Pathology (ISUP) nucleolar grade 2 or 3 with mostly basally located nuclei. Tumor cells from 17 of 24 TSC-associated PRCC showed strong, diffuse labeling for CA-IX (100%), CK7 (94%), vimentin (88%), CD10 (83%), and were uniformly negative for succinate dehydrogenase subunit B (SDHB), TFE3 and AMACR. Gains of chromosomes 7 and 17 were found in 2 tumors, whereas chromosome 3p deletion and TFE3 translocations were not detected. In this study, we reported a sizable cohort of renal tumors seen in TSC and were able to identify them as different morphotypes which may help to expand the morphologic spectrum of TSC-associated RCC.
Estrogens play a pivotal role in the development and progression of prostate cancer (PCa). Their actions are mediated by estrogen receptors (ERs), particularly ERβ in the prostate epithelium. With the discovery of ERβ isoforms, data from previous studies that focused principally on the wild-type ERβ (ERβ1) may not be adequate in explaining the still controversial role of ERβ(s) in prostate carcinogenesis. In this study, using newly generated isoform-specific antibodies, immunohistochemistry (IHC) was performed on a tumor microarray comprised of 144 specimens. IHC results were correlated with pathological and clinical follow-up data to delineate the distinct roles of ERβ1, ERβ2, and ERβ5 in PCa. ERβ2 was commonly found in the cytoplasm and was the most abundant isoform followed by ERβ1 localized predominantly in the nucleus, and ERβ5 was primarily located in the cytoplasm. Logistic regression analyses demonstrated that nuclear ERβ2 (nERβ2) is an independent prognostic marker for prostate specific antigen (PSA) failure and postoperative metastasis (POM). In a Kaplan–Meier analysis, the combined expression of both nERβ2 and cytoplasmic ERβ5 identified a group of patients with the shortest POM-free survival. Cox proportional hazard models revealed that nERβ2 predicted shorter time to POM. In concordance with IHC data, stable, ectopic expression of ERβ2 or ERβ5 enhanced PCa cell invasiveness but only PCa cells expressing ERβ5 exhibited augmented cell migration. This is the first study to uncover a metastasis-promoting role of ERβ2 and ERβ5 in PCa, and show that the two isoforms, singularly and conjointly, have prognostic values for PCa progression. These findings may aid future clinical management of PCa.
Distinguishing a well-differentiated hepatocellular carcinoma (HCC) from normal and cirrhotic liver tissue or benign liver nodules, such as hepatic adenoma (HA) and focal nodular hyperplasia (FNH), may be very difficult in some cases, particularly in small needle core biopsies. We studied the expression of Glypican-3 (GPC3) and CD34 in 107 cases of HCC, 19 cases of HA, and 16 cases of focal nodular hyperplasia (FNH). In addition, we studied GPC3 expression in 225 cases of nonhepatic human tumors with epithelial differentiation. Ninety-four of 107 cases (88%) of HCC showed focal or diffuse cytoplasmic GPC3 staining, whereas all HA and FNH cases were GPC3-negative, and only 7 of 225 cases (3%) of nonhepatic tumors with epithelial differentiation expressed GPC3. The sensitivity and specificity of GPC3 for HCC was 88% and 97%, respectively. There were three CD34 staining patterns observed in hepatic tissue: negative, incomplete positive, and complete positive. In negative staining pattern, only blood vessels in portal triads or rare sinusoidal spaces immediately adjacent to portal tracts were positive. The negative staining pattern was seen in normal or cirrhotic liver tissue only. The complete CD34 staining pattern showed virtually all sinusoidal spaces with CD34-positive staining throughout the lesion. The complete CD34 staining pattern was seen in virtually all cases of HCC and in only some cases of HA and FNH. The incomplete CD34 staining pattern was characterized by either CD34 positivity in virtually all sinusoidal spaces in some but not all nodules or CD34 positivity in the peripheral sinusoidal spaces adjacent to portal triads. The incomplete CD34 staining pattern was seen in rare cases of HCC and in most cases of HA and FNH. We conclude that GPC3 is a very specific marker not only for differentiating HCC from nonhepatic tumors with epithelial differentiation, but also for differentiating HCC from HA and FNH. GPC3 immunoreactivity, in combination with a complete CD34 immunostaining pattern, greatly facilitates the accuracy of distinguishing between malignant hepatic lesions and benign mimickers.
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