CYP24A1-induced vitamin D insufficiency promotes breast cancer growth.

Vitamin D plays a critical role in tissue homeostasis by regulating the expression of genes affecting cell proliferation, differentiation, and apoptosis. The vitamin D 24-hydroxylase CYP24A1 functions in vitamin D target tissues to degrade the hormonal form of vitamin D. Existing knowledge regarding dysregulated CYP24A1 expression supports its candidacy as a putative oncogene. Here, we found that the suppression of constitutive CYP24A1 expression conferred target cells with increased susceptibility to apoptosis and consequently inhibited anchorage-independent growth in breast carcinoma cells. In addition, suppression of vitamin D metabolism following knockdown of CYP24A1 significantly reduced tumor growth in vivo. These data provide substantial evidence for a pro-survival and stimulatory oncogenic effect of CYP24A1 in breast carcinoma cells.

Elevated expression of the retinoic acid-metabolizing enzyme CYP26C1 in primary breast carcinomas.

Retinoic acid (RA)-metabolizing enzyme CYP26A1 has been shown to have increased expression levels in breast cancers and to effectively promote the survival of breast carcinoma cells, implying a potential oncogenic function. However, the expression of CYP26C1, another CYP26 family member, in primary breast carcinoma remains to be clarified. In the present study, we examined the expression of CYP26C1 by immunohistochemistry, using three different types of microarray, and observed strong cytoplasmic staining of CYP26C1 in 73 of the 219 (33.3 %) breast carcinomas. In contrast, CYP26C1 was not expressed in normal ductal and lobular cells in non-neoplastic tissue. Interestingly, increased expression of CYP26C1 was significantly associated with a high Ki-67 labeling index and a grade of tumor. However, CYP26C1 immunoreactivity was not associated with clinicopathological variables, including primary tumor status, lymph node involvement, distant metastasis, and tumor stage. In addition, CYP26C1 positivity was independent of the expression status of the hormone receptors and immunohistochemical surrogates for the intrinsic subtypes of breast cancer. This report is the first to demonstrate elevated expression of CYP26C1 in primary breast carcinomas. Based on the RA-catabolizing activity of CYP26C1, our data suggest that CYP26C1 expression may contribute to neoplasia in the breast.

NOTCH2 signaling confers immature morphology and aggressiveness in human hepatocellular carcinoma cells.

The NOTCH family of membranous receptors plays key roles during development and carcinogenesis. Since NOTCH2, yet not NOTCH1 has been shown essential for murine hepatogenesis, NOTCH2 rather than NOTCH1 may be more relevant to human hepatocarcinogenesis; however, no previous studies have supported this hypothesis. We therefore assessed the role of NOTCH2 in human hepatocellular carcinoma (HCC) by immunohistochemistry and cell culture. Immunohistochemically, 19% of primary HCCs showed nuclear staining for NOTCH2, indicating activated NOTCH2 signaling. NOTCH2-positive HCCs were on average in more advanced clinical stages, and exhibited more immature cellular morphology, i.e. higher nuclear-cytoplasmic ratios and nuclear densities. Such features were not evident in NOTCH1­positive HCCs. In human HCC cell lines, abundant NOTCH2 expression was associated with anaplasia, represented by loss of E-cadherin. When NOTCH2 signaling was stably downregulated in HLF cells, an anaplastic HCC cell line, the cells were attenuated in potential for in vitro invasiveness and migration, as well as in vivo tumorigenicity accompanied by histological maturation. Generally, inverse results were obtained for a differentiated HCC cell line, Huh7, manipulated to overexpress activated NOTCH2. These findings suggested that the NOTCH2 signaling may confer aggressive behavior and immature morphology in human HCC cells.

Early Stages of Hyaline Membrane Formation Detected in Alveolar Mouths in Diffuse Alveolar-Damage-Associated Diseases: A Detailed Immunohistochemical Study.

To study the early stages of hyaline membrane (HM) formation, diffuse alveolar damage (DAD) was thoroughly investigated using immunohistochemical methods in 15 autopsy cases, which consisted of various types of interstitial pneumonias and pulmonary diseases derived from nonmalignant or malignant diseases. Alveolar mouths (AMs) that were presumed to be normal were ultrastructurally examined in detail, by using pulmonary tissues in the pneumothorax. It is interesting to note that during the initial stages of HM formation in AMs, fragmented eosinophilic masses were closely attached to AMs as irregular fragments or by a cap-like structure. The ultrastructure revealed some distance between the capillary spaces and surface epithelium of the AMs, indicating that the epithelial cells at the AMs might be often easily damaged even by minor stimuli; they can be considered as "locus minoris resistentiae." HMs were found to be formed initially at the site of AMs derived from fragmented eosinophilic masses in not only pulmonary but also extrapulmonary diseases, including both nonmalignant and malignant diseases. These irregular eosinophilic masses, representing the early shape of HMs, were immunohistochemically positive for the epithelial membrane antigens, namely, surfactant protein A and factor VIII antigen, and occasionally for KL-6 and cytokeratins. These results suggested that fragmented irregular masses represent the initial phase of HM formation. Five of 15 cases were focally negative for KL-6 at the initial irregular mass of HMs. Because KL-6 is one of the fundamental components of pulmonary surface elements, it needs to be studied further by detailed clinicopathological examination.

The retinoic acid-metabolizing enzyme CYP26A1 upregulates fascin and promotes the malignant behavior of breast carcinoma cells.

The retinoic acid (RA)-metabolizing enzyme CYP26A1 has been shown to efficiently enhance the oncogenic potential of breast cancer, suggesting a potential oncogenic function. We previously demonstrated that CYP26A1 confers unique cell survival properties by modulating the expression of a variety of genes and identified a number of genes that drive the cells into the oncogenic state. Accumulating evidence suggested that fascin is overexpressed in various types of cancer, primarily leading to increased cell motility. Therefore, in the present study, we examined fascin, an actin-bundling protein, using immunohistochemical and SA-ß-gal staining as well as TUNEL and colony forming assays. The results of the present study showed that the expression levels of fascin increased significantly in response to CYP26A1 overexpression and, conversely, treatment with all-trans RA downregulated the expression of fascin. In addition, primary breast carcinoma samples, particularly hormone receptor-negative carcinomas and CYP26A1-overexpressing cancers, expressed elevated levels of fascin. Notably, fascin contributed to the ability of breast carcinoma cells to escape premature senescence and exhibit enhanced cell apoptotic resistance, promoting anchorage-independent growth properties. Fascin also promoted cell motility and the invasiveness of CYP26A1-expressing breast carcinoma cells. These data suggest that fascin expression is modulated by the intracellular RA status regulated by the expression of CYP26A1 and plays a significant role in the malignant behavior of CYP26A1-expressing breast carcinoma cells. CYP26A1 exerts oncogenic functions during breast carcinogenesis. Therefore, CYP26A1-mediated oncogenic characteristics may be partially responsible for the elevated expression of fascin.

Investigation of aluminum and iron deposition on metaplastic bones in three patients with diffuse pulmonary ossification.

Diffuse pulmonary ossification (DPO) is a rare pulmonary lesion. DPO is typically detected at autopsy rather than premortem. Recently, however, several cases were diagnosed antemortem using computed tomography, high-resolution computed tomography, or video-assisted thoracic surgery. In the present study, we evaluated DPO at autopsy from two patients with post-myocardial infarction (cases 1 and 3) and one patient with duodenal cancer (case 2). Multiple metaplastic bones (nodular in case 1 and 3 or dendriform in case 2) were detected in these three cases. In an attempt to detect aluminum and iron deposition in these metaplastic bones, histochemical investigations were performed. The two nodular types of one and three cases were positive for aluminum and iron, but the dendriform type of case 2 was positive only for aluminum. The depositions occurred in a linear pattern along the calcifying front. It is of great interest that these deposition patterns were similar to those of bones from three previously reported DPO cases and from the bones of hemodialysis patients. It is suggested that these abnormal metal depositions in the calcifying front might disturb the normal mineralization processes of the metaplastic bones, although no morphological abnormality was detected, except for dense black color of calcifying front lines. Further investigations are needed in more patients with DPO to obtain more information on this topic.

Usefulness of KL-6 in the subtyping of intraductal papillary mucinous neoplasia of the pancreas, including carcinoma, dysplasia, and hyperplasia.

KL-6 is known as a useful serum biomarker of the disease activity in interstitial pneumonias. We investigated its usefulness as a biomarker for subtyping intraductal papillary mucinous neoplasms (IPMNs) of the pancreas. IPMNs are generally divided into 4 subtypes, namely pancreatobiliary (PB), intestinal (INT), gastric (GS), and oncocytic (ONC). Aside from the KL-6 antibody, the MUC1, MUC2, MUC5AC, MUC6, and MIB-1 antibodies were also examined. Eighteen IPMN cases were examined, including 12 cases of intraductal papillary mucinous carcinomas (IPMCs) simultaneously associated with dysplasia (IPMDs) and hyperplasia (IPMHs) and 6 IPMD cases with IPMH. KL-6 antibody was positive in the 8 IPMC cases, corresponding to a MUC2-negative PB subtype, but negative in 4 IPMC cases, corresponding to the INT subtype, which is positive for MUC2. IPMD of moderate-to-severe degree positively stained for the KL-6 antibody in the IPMC cases of the PB subtype but not in those of the INT subtype. The IPMH cases were mostly negative for KL-6, similar to the mild IPMD cases. In the 6 cases of mild IPMD and/or IPMH, KL-6 and MUC2 expressions were mostly negative. In conclusion, the KL-6 antibody is immunohistochemically a good biomarker of the PB subtype of IPMC, but not the INT subtype. Identifying IPMN subtypes based on KL-6 stainability would be useful. Clinicopathological studies with more IPMC cases might be needed for further progress in this field of study.

Increased expression of the retinoic acid-metabolizing enzyme CYP26A1 during the progression of cervical squamous neoplasia and head and neck cancer.

BACKGROUND: Retinoic acid (RA) is a critical regulator of cell differentiation, proliferation, and apoptosis in various cell types. Recently, the RA-metabolizing enzyme CYP26A1 (cytochrome P450, family 26, subfamily A, polypeptide 1) has been shown to have an oncogenic function in breast carcinogenesis. However, the relevance of elevated CYP26A1 expression in human cancers remains to be clarified. METHODS: We immunohistochemically examined the expression of CYP26A1 in cervical squamous cell carcinoma (SCC) and its precursors, including low- and high-grade squamous intraepithelial lesions (LSIL and HSIL, respectively), as well as head and neck cancer (HNC). The association between CYP26A1 expression and a number of clinicopathological parameters was also evaluated. RESULTS: CYP26A1 was not expressed in normal cervical epithelium. CYP26A1 expression was present in LSIL but limited to basal and parabasal cells. HSIL cases exhibited strong nuclear expression of CYP26A1 and mixed cytoplasmic expression patterns with widely distributed expression toward the epithelial surface. Importantly, strong cytoplasmic staining of CYP26A1 was observed in 19 of 50 (38%) patients with cervical SCC. Elevated expression of CYP26A1 was significantly associated with younger age (<50 years) and lymph node involvement (pN). Similarly, CYP26A1 was not expressed in non-neoplastic tissues of the head and neck, but strong cytoplasmic staining of CYP26A1 was observed in 52 of 128 (41%) HNC cases. Such strong CYP26A1 expression was significantly associated with the primary tumor stage of carcinomas (pT) and the pathological tumor-node-metastasis (pTNM) stage in HNC. CONCLUSION: Our results indicated an elevated CYP26A1 expression in malignant and precancerous dysplastic lesions of the human cervix, which also increased with the progression of cervical squamous neoplasia. In addition, this report is the first to demonstrate the increased expression of CYP26A1 in HNC and its significant correlation with primary tumor growth. These data suggested that CYP26A1 overexpression might contribute to the development and progression of cervical malignancies and squamous neoplasia of the head and neck.

Immunohistochemical analysis of invasive micropapillary carcinoma pattern in four cases of gastric cancer.

Gastric cancer with the invasive micropapillary carcinoma (IMPC) pattern has been reported to be a variant with poor prognosis and rapid progression. To the best of our knowledge, only 4 cases of gastric cancer from Japan and 11 cases from Korea have been reported to contain the IMPC pattern. In the present study, 4 cases of gastric cancer containing the IMPC pattern from 2 Japanese men and 2 Japanese women are reported. The cancer tissues, including a recurrent lesion in 1 case and lymph node metastases in 2 other cases, were examined immunohistochemically to identify suitable markers for demonstrating the peculiar "inside out" pattern of IMPC and for analyzing HER2 expression. A characteristic IMPC pattern occupied more than 10% of each cancer tissue in these 4 cases. Lymphatic invasions were very often detected; in fact, lymph node metastases were detected in 3 out of 4 cases. The unique "inside out" pattern in IMPC was clearly revealed in all cases by staining with antibodies to both epithelial membrane antigen (EMA) and KL-6, but not with an antibody to CD10. HER2 was positive in 3 of 4 cases with the IMPC pattern, including cases with a recurrent lesion or lymph node metastases. Fluorescence in situ hybridization (FISH) analyses disclosed positive results in case 1, and case 3 including lymph node metastatic foci. Highest FISH titer was 6.8 in case 1, revealing marked amplification of HER-2 gene. Four cases of gastric cancer with the IMPC pattern were reported. EMA and KL-6, but not CD10, were particularly useful markers for visualizing the characteristic "inside out" pattern of the IMPC pattern in stomach cancers, similar to the markers for breast and urinary bladder cancers.

Composite paraganglioma and ganglioneuroma in the retroperitoneum: a case report.

Reports of a composite paraganglioma (PG) and ganglioneuroma (GN) in the retroperitoneum are rare. In the present case, dynamic computed tomographic (CT) findings showed a 30 × 22 × 20 mm tumor that was located in the retroperitoneum and which was dissociated from pancreatic tissue and the left adrenal gland. The markedly reddish tumor showed a clear margin and central multicystic changes on the cut surface. The tumor was composed of two major components, the PG and the GN. The paraganglionic cells in the PG component, which were arranged in a nested pattern, occupied the main and central part of the tumor. Both ganglionic cells and Schwann cells in the GN were located in a unorganized pattern in the periphery. The paraganglionic cells exhibited a Zellballen pattern, which consisted of an association of edematous vascular-rich stroma and focal hemorrhage, resulting in multicystic changes. These centrally located tumor cells were pleomorphic in part and did not have mitotic figures. In the periphery, Schwann cells, which were arranged in an obscure and fascicular pattern that was intermingled with large ganglionic cells, were located adjacent to the PG component with a mostly sharp margin. With higher magnification, the border was not as sharp, as revealed especially with chromogranin-A immunostain, in which both the PG and GN components were focally intermingled with each other. The histogenesis of the composite PG and GN was thought to be extraadrenal neural crest cells in the retroperitoneum because the tumor was not located in the adrenal gland or the Zuckerkandl organ, according to the CT findings. The immunohistochemical findings of this rare case of a composite PG and GN in the retroperitoneum are reported with a focus on the peculiar arrangement of these two components.

Marked infiltration of eosinophils in necrotizing granulomas in the resected hepatic bed after cholecystectomy resulting from gallbladder cancer and metastatic liver cancer is associated with peculiar peripheral eosinophilia.

It is known that after transurethral resection of the prostate (TUR-P) or a bladder tumor (TUR-BT), necrotizing granuloma formation associated with massive eosinophil accumulation can be detected at the site of the scar, revealing marked eosinophilia. This condition is called post-TUR prostatitis or cystitis. In the present study, we noticed a similar phenomenon in five patients who underwent cholecystectomy, of whom four had gallbladder adenocarcinoma and one had metastatic liver cancer originating from the rectum. We detected necrotizing granulomas with massive eosinophil accumulation, associated with marked eosinophilia. To induce these phenomena, the interval between the first operation (i.e., cholecystectomy) and the second operation (i.e., resection of the hepatic bed and extrahepatic bile duct) is very important. If the interval was 1 week, no granuloma formation was detected. On the other hand, if it was more than 2 weeks, the resected hepatic bed contained necrotizing granulomas with substantial eosinophil accumulation combined with an increase in peripheral eosinophilia (up to 34% in one case). Secondary resection was necessary to induce eosinophilia after cholecystectomy. In this sense, malignancies possessed a relationship with delayed eosinophilia. In the granulomas, some foreign body-type multinucleated giant cells were positive for both anti-interleukin (IL)-5 and CD68 antibodies. In sharp contrast, no eosinophilia was detected after cholecystectomy, with or without hepatic resection consequent to severe adhesion. Clinicians as well as pathologists should keep in mind that these peculiar phenomena of eosinophil accumulation surrounding the necrotizing granulomas and peripheral eosinophilia after cholecystectomy could occur.

Review of renal carcinoma associated with Xp11.2 translocations/TFE3 gene fusions with focus on pathobiological aspect.

The concept of Xp11.2 renal cell carcinoma (RCC) was recently established as a tumor affecting 15% of RCC patients <45 years. Many patients present with advanced stage with frequent lymph node metastases. Histologically, Xp11.2 RCC is characterized by mixed papillary nested/alveolar growth pattern and tumor cells with clear and/or eosinophilic, voluminous cytoplasm. Neoplastic cells show intense nuclear immunoreactivity to TFE3, while focal immunostaining for melanocytic markers, including melanosome-associated antigen or Melan A in some cases, are also noted. Alpha smooth muscle actin and TFEB are consistently negative. Ultrastructurally, the ASPL-TFE3 RCC variant contains rhomboid crystals in the cytoplasm, similar to that observed in alveolar soft part sarcoma. The fusion of the TFE3 gene with several different genes, including ASPL(17q25), PRCC(1q21), PSF(1q34), NonO (Xq12) and CLTC (17q23) have been identified to date. The behavior of Xp11.2 RCC in children and young adults is considered as indolent even when diagnosed at advanced stage, including lymph node metastasis. However, Xp11.2 RCC in older patients behaves in a more aggressive fashion. Therapy includes nephrectomy with extended lymphadenectomy. There may be a role for new protease inhibitors in advanced inoperable disease. Further research is required to correlate clinical behavior with the expanding genetic spectrum of this tumor, and to establish standard therapy protocols for primary and metastatic lesions.

Enhanced expression of retinoic acid-metabolizing enzyme CYP26A1 in sunlight-damaged human skin.

Vitamin A deficiency (VAD) is associated with increased susceptibility to carcinogenesis. CYP26A1, the gene encoding a cytochrome P450 enzyme specifically involved in metabolic inactivation of retinoic acid (RA), the most active vitamin A derivative, has been shown to result in a state of functional VAD of the cell. Recently, we demonstrated that CYP26A1 efficiently promotes cell survival properties and eventually contributes to the carcinogenic process, implying roles as an oncogene. To clarify the possible association between VAD caused by CYP26A1 expression and the development of human epithelial neoplasia, we examined whether enhanced expression of CYP26A1 might be observed in various lesions of human skin. We report here that basal keratinocytes showed only weak positivity of CYP26A1 in sunlight-nonexposed areas, whereas strong positive staining was observed in skin from chronically sunexposed body areas and in epidermis that had the dysplastic changes known as actinic keratosis. However, we found no expression of constitutive CYP26A1 in skin malignancies such as squamous cell carcinomas. Our observation suggests an involvement of enhanced CYP26A1 expression causing a functional VAD state in skin that can potentially lead to neoplastic transformation of keratinocytes in an early phase during skin carcinogenesis.

Acquired cystic disease-associated renal cell carcinoma: an immunohistochemical and fluorescence in situ hybridization study.

Acquired cystic disease (ACD)-associated renal cell carcinoma (RCC) has been recently identified. However, there are only a few genetic studies to date. In this article, we performed an immunohistochemical and fluorescence in situ hybridization (FISH) study for six cases including one case with sarcomatoid change. As a result, we observed frequent immunohistochemical expression of AMACR. FISH of chromosome 3 showed trisomy for three cases, monosomy for two cases, and disomy for one case. Additionally, FISH of chromosome 16 showed trisomy for three cases, monosomy for two cases, and both trisomy and monosomy for one case. Furthermore, both the carcinomatous area and the sarcomatoid area of one ACD-associated RCC with sarcomatoid change revealed monosomy of chromosomes 3, 9, and 16 but showed disomy of chromosome 14. In conclusion, the numerical abnormalities of chromosomes 3 and 16, irrespective of gain or loss, may be characteristic of ACD-associated RCC.

Chromophobe renal cell carcinoma with prominent lymph node metastasis and polysomy of chromosome 21: poorly differentiated form or "presarcomatoid" form?

Lymph node metastasis of chromophobe renal cell carcinoma (RCC) is extremely rare. It has been recently reported that sarcomatoid chromophobe RCC frequently show polysomy of chromosomes 1, 2, 6, 10, and 17. In this article, we report an unusual case of chromophobe RCC. A 42-year-old Japanese woman presented with hematuria and complained of inguinal pain 2 months after the initial symptoms. Radical nephrectomy and renal hilar lymphadenectomy were performed. The tumor was 8 cm in greatest diameter; its cut surface was beige in color. Large metastasis to the renal hilar lymph node was identified. Histological examination of the right renal tumor met the criteria of chromophobe RCC. In addition to histological findings of typical chromophobe RCC, small cell foci, comedo-like necrosis, trabecular growth pattern, and sclerosing stroma were observed. However, no sarcomatoid foci were identified anywhere, despite extensive tumor sampling including lymph node lesions. Immunohistochemically, neoplastic cells were positive for E-cadherin and CD117 (c-kit). Ultrastructurally, tumorous cells contained abundant mitochondria and cytoplasmic microvesicles. Fluorescence in situ hybridization showed monosomy of chromosomes 2 and 10 and polysomy of chromosome 21. Finally, we suggest that this tumor may show the poorly differentiated or presarcomatoid form of chromophobe RCC.

Immunohistochemical application of S100A1 in renal oncocytoma, oncocytic papillary renal cell carcinoma, and two variants of chromophobe renal cell carcinoma.

S100A1 is a calcium-binding protein and a member of the S100 family. Recently, S100A1 immunohistochemistry may be an available marker in the differential diagnosis between renal oncocytoma and chromophobe renal cell carcinoma (RCC). However, there are no reports on S100A1 expression in oncocytic papillary RCC that has been recently identified. In this article, we immunohistochemically examined the expression of S100A1 protein in 18 renal tumors including 4 renal oncocytoma, 10 chromophobe RCCs, and 4 oncocytic papillary RCCs. All the cases of renal oncocytoma and oncocytic papillary RCC showed a positive reaction for S100A1 with cytoplasmic pattern. In chromophobe RCC, 3 of 4 tumors with typical variant and 4 of 6 tumors in eosinophilic variant were completely negative for S100A1. Finally, S100A1 immunohistochemistry may be useful in distinguishing renal oncocytoma from chromophobe RCC, but it may be of no use in the differential diagnosis between renal oncocytoma and oncocytic papillary RCC.

Review of acquired cystic disease-associated renal cell carcinoma with focus on pathobiological aspects.

Acquired cystic disease (ACD)-associated renal cell carcinoma (RCC) is a recently established entity. In this article, we introduce the general view of this new entity. Macroscopically, the disease exclusively occurs in ACD and may arise as a dominant mass or non-dominant masses. Histologically, the tumor is characterized by a microcystic pattern, neoplastic cells with an eosinophilic or oncocytic cytoplasm and frequent intratumoral oxalate crystal deposition. Prominent nucleoli of tumor cells are often observed. Immunohistochemically, neoplastic cells are generally positive for AMACR but negative for cytokeratin 7. Ultrastructurally, neoplastic cells contain abundant mitochondria in the cytoplasm. Genetically, the gain of chromosomes 3, 7, 17 and abnormality of the sex chromosome were frequently observed in several studies. In conclusion, ACD-associated RCC may be widely recognized as a distinct entity in the near future because this tumor is morphologically and genetically different from other renal tumor entities that have been previously established.

Nicotine-mediated suppression of the retinoic acid metabolizing enzyme CYP26A1 limits the oncogenic potential of breast cancer.

Tobacco smoke influences cancer development in tissues that are not directly exposed, and epidemiological studies have indicated that smoking women might experience decreased risk of breast cancer as a result of antiestrogenic effects. However, it remains to be clarified whether nicotine, one of the major addictive and best-investigated constituents of tobacco smoke, has any effect on breast cancer. Our recent work demonstrated that the retinoic acid metabolizing enzyme CYP26A1 enhances oncogenic and cell survival properties of breast carcinoma cells, implying a role as an oncogene. Here, we present evidence that nicotine significantly suppresses constitutive expression of CYP26A1, and that cells treated with nicotine exhibit enhanced sensitivity to apoptosis. In addition, nicotine may inhibit anchorage independent growth, cellular invasiveness and motility. These data show that nicotine can limit CYP26A1-mediated oncogenic characteristics, and suggest mechanisms by which nicotine might inhibit breast cancer development.

Re-evaluation of histological type by immunohistochemical and genetic study of transcription factors (TFE3 and TFEB) of VHL gene mutation-negative clear cell renal cell carcinoma and other special types of renal tumor.

Translocation-type renal carcinoma has been recently discovered, and it is possible that this tumor may have been previously diagnosed as other types of renal tumor. We have subjected 41 renal tumors, including VHL gene mutation-negative clear cell renal cell carcinoma (RCC), papillary RCC, and chromophobe RCC, to immunohistochemistry of transcription factor E3 (TFE3) and TFEB. All tumors were histologically evaluated by additional immunohistochemical study. As a result, 5 tumors showed a positive reaction for TFE3 with a range from 1+ to 2+ in intensity. No tumors were positive for TFEB. In 5 tumors immunohistochemically positive for TFE3, chimeric transcripts including ASPL-TFE3, PRCC-TFE3, CLTCTFE3, PSF-TFE3, or Nono-TFE3 were not detected. The diagnosis of 6 tumors was changed by reevaluation through retrospective histological and immunohistochemical study. In 4 of 6 tumors, the diagnosis of clear cell RCC was changed to chromophobe RCC. In 1 tumor, oncocytoma was detectable, and RCC with rhabdoid features and sarcomatoid changes was detected in 1 tumor. Finally, the cutoff value of TFE3 immunohistochemistry should be more than 2+ with a wide range. The translocation-type renal carcinoma seems to be quite rare.

Fascin-1 expression correlates with repression of E-cadherin expression in hepatocellular carcinoma cells and augments their invasiveness in combination with matrix metalloproteinases.

Expression of fascin-1, an actin bundling protein, is a poor prognostic factor in hepatocellular carcinoma (HCC). However, its biological role in HCC cells remains unclear. Using human HCC tissues and cell lines HLE, Hep3B, and Huh7, we investigated whether fascin-1 is involved in epithelial-mesenchymal transition (EMT) and increases invasiveness, thus serving as a promoter of cancer aggressiveness. Immunohistochemical analysis revealed that fascin-1 expression in 19% of primary HCCs was associated with repression of E-cadherin expression, indicating EMT. In vitro, HLE cells showed high fascin-1 expression, loss of E-cadherin, and efficient invasion through Matrigel. Knockdown of fascin-1 significantly repressed invasiveness of the HLE cells and slightly induced E-cadherin expression. In contrast, Huh7 cells had low fascin-1 levels, high E-cadherin expression, and were expectedly non-invasive. However, forced overexpression of fascin-1 conferred only modest invasiveness without E-cadherin repression, indicating that fascin-1 alone cannot effectively stimulate invasiveness or EMT. Furthermore, Hep3B cells were non-invasive despite high fascin-1 expression. Nevertheless, fascin-1 overexpression dramatically increased the migratory potential of Huh7 cells. We then evaluated matrix metalloproteinases (MMPs) 2 and 9 from the HCC cell lines. Significant MMP secretion was only found in HLE cells. Although MMP levels were not elevated in fascin-1-overexpressing Huh7 cells, their invasiveness was remarkably augmented by coculture with HLE cells, and was suppressed in the presence of an MMP inhibitor. In conclusion, we propose that fascin-1 primarily acts as a migration factor associated with EMT in HCC cells and facilitates their invasiveness in combination with MMPs.