[Primary testicular diffuse large B-cell lymphoma: A clinicopathological analysis].

OBJECTIVE: To investigate the clinicopathological features, immunophenotype and treatment of primary testicular diffuse large B-cell lymphoma (DLBCL). METHODS: We retrospectively analyzed the pathomorphological characteristics and immunohistochemical markers of 23 cases of primary testicular DLBCL as well as their clinicopathological features with a review of the relevant literature. The patients were aged 48－76 (mean 61.4) years, 82.6% over 50 years, and all clinically presented with painless progressive unilateral testicular swelling, 9 cases in the left and the other 14 in the right testis. RESULTS: Histologically, the lymphomas were composed of large atypical cells with prominent karyokinesis and diffusely infiltrated the testicular parenchyma. The neoplastic cells were positive for B-cell markers. Five of the patients were followed up for 2 to 32 months, of whom 4 survived and 1 died at 9 months. CONCLUSIONS: Primary testicular DLBCL is a rare tumor with an invasive biological behavior, mostly found in elderly males and easily misdiagnosed or missed in diagnosis. Histopathology plays a key role and immunohistochemical markers are of high value in the definite diagnosis and differential diagnosis of the tumor.

[Clinicopathological characterization of non-Hodgkin lymphoma of the prostate].

OBJECTIVE: To study the clinicopathological characteristics of non-Hodgkin lymphoma (NHL) of the prostate. METHODS: We collected the clinical data on 6 cases of NHL of the prostate pathologically confirmed between 2001 and 2017. The patients were aged 49－76 (median 62) years old, with the main clinical manifestations of painless swelling of the prostate and lower urinary tract obstruction. We analyzed the clinical features and the results of histological detection, immunohistochemical staining and B-cell gene rearrangement assay, and explored the clinicopathological characteristics and differential diagnosis of the disease based on the relevant literature. RESULTS: Histological detection revealed diffuse large B-cell lymphoma (DLBCL) in 4 cases (66.7%), B-lymphoblastic lymphoma (B-LBL) in 1 (16.7%), and Burkitt lymphoma (BL) in another (16.7%). DLBCL was histologically characterized by diffuse oval or round medium-to-large-sized lyphoid cells with an infiltrative growth pattern, B-LBL by monotonous small-to-medium-sized lymphoid cells with prominet mitosis and apoptosis, and BL by diffuse and monotonous medium-sized neoplastic cells with round or oval nuclei, an infiltrative growth pattern, scanty cytoplasm and visible mitosis. One of the DLBCL patients received 5 doses of R-CHOP chemotherapy and has been followed up to the present time, while the other 3 were lost to follow-up; the B-LBL patient died at 1 month after diagnosis; and the BL patient gave up treatment. CONCLUSIONS: Non-Hodgkin's lymphoma of the prostate mostly presents as diffuse large B-cell lymphoma, and its diagnosis depends on immunohistochemistry and related molecular detection as well as its clinical and histopathological manifestations.

[Clinicopathologic features of testicular seminoma with syncytiotrophoblastic cells: Analysis of 3 cases and review of the literature].

OBJECTIVE: To investigate the clinical and histopathologic features of testicular seminoma with syncytoplasmic trophoblastic components. METHODS: Using light microscopic staining, we analyzed the clinical and histopathologic characteristics, diagnosis, differential diagnosis and prognosis of 3 cases of testicular seminoma with syncytoplasmic trophoblastic components, and reviewed the relevant literature. RESULTS: All the 3 cases were typical seminoma with syncytiotrophoblastic giant cells. Immunohistochemistry showed strong expressions of CD117 OCT-4, SALL4 and PLAP in diffuse tumor cells, and that of hCG in syncytiotrophoblastic cells. Continuous monitoring and consultation exhibited normal levels of serum ß-hCG in all the cases after postoperative chemotherapy. CONCLUSIONS: Testicular seminoma with syncytiotrophoblastic giant cells and increased serum ß-hCG is a rare subtype, which occurs mostly in young people, sensitive to chemotherapy postoperatively and with a relatively good prognosis.

MYC/BCL2 Co-Expression Is a Stronger Prognostic Factor Compared With the Cell-of-Origin Classification in Primary CNS DLBCL.

Primary central nervous system (CNS) diffuse large B-cell lymphoma (DLBCL) is a subtype of DLBCL with an unfavorable prognosis and a poor response to the treatment. As we know, DLBCL is stratified into germinal center B-cell (GCB)-like and activated B-cell (ABC)-like subtypes with different prognosis according to their gene-expression characteristics. In this study, we analyzed a case series of 77 patients with primary CNS DLBCL. A difference in prognosis of GCB-like and ABC-like subtypes was noticed, but no statistical significance was found. However, significant prognostic value of MYC/BCL2 co-expression was shown. The cases with MYC/BCL2 co-expression did not show any predominance of the 2 subtypes in our cases. Furthermore, patients with MYC/BCL2 co-expression had significantly worse overall survival for both cell of origin (COO) subtypes. We conjecture that MYC/BCL2 co-expression is associated with a poorer prognosis and is independent of COO classification. Moreover, the data suggest that MYC/BCL2 co-expression is superior to COO classification assessed by immunohistochemical analysis in patients with primary CNS DLBCL.

P16 overexpression in BRAF-mutated gastrointestinal stromal tumors.

BACKGROUND: The aims of this study were to analyze the histopathology, immunophenotype, molecular features, and prognosis in cases of BRAF-mutated gastrointestinal stromal tumors (GISTs) and to examine the p16 expression in these tumors, and further discuss its effects on tumor formation and progression. METHODS: In all, 283 GIST cases (201 KIT mutants, 12 PDGFRA mutants and 70 wild-type) from the 2010 to 2014 surgical pathology files of the Department of Pathology at Nanjing Jinling Hospital were analyzed for mutations in BRAF exon 15. Patient follow-up and clinical data were collected if available in the medical records. To determine the clinicopathological features and potential molecular mechanism, the authors examined 10 BRAF-mutated GIST cases for KIT, DOG1, SMA, desmin, S-100, Ki-67 and p16 expression. RESULTS: The authors identified 10 cases (3.5%) of BRAF (V600E) mutations in a series of 283 primary GISTs, without KIT (exons 9, 11, 13, 17) or PDGFRA (exons 12, 18) gene mutations. All 10 cases exhibited spindle-cell features, and the morphology and immunophenotype of these cases were no different from those in cases of KIT-mutated GISTs. The clinical results indicated that BRAF-mutated GISTs tended to occur more frequently in females (7/10), older individuals (mean age, 54.9 years) and the stomach (7/10), and that these tumors were low risk and exhibited low recurrence and mortality rates. Two different forms of p16 were identified, which presented with simultaneously strong and diffuse nuclear and cytoplasmic expression patterns. CONCLUSION: GISTs with the BRAF V600E mutation are relatively benign tumors with a distinctive molecular mechanism. The expression of the nuclear and cytoplasmic forms of p16 represent two independent mechanisms, and both seemed to control proliferation in response to oncogenic stimuli, protecting the cell from malignant transformation in BRAF-mutated GISTs.

Ovarian small-cell carcinoma hypercalcemic type successfully treated: a case report and literature review.

Ovarian small-cell carcinoma hypercalcemic type (OSCCHT) is a relatively rare and highly fatal gynecological malignancy. Prognosis is generally poor, and no treatment guidelines are offered. Here, we report a case of OSCCHT successfully treated by complete excision and a postoperative chemotherapy scheme of carboplatin and paclitaxel. A 29-year-old female with with pelvic mass and significantly increased serum calcium (4.90 mmol/L) was referred to our hospital on August 22, 2013. Abdominal ultrasonography and computed tomography revealed a pelvic nonhomogeneous echo of a 113×102 mm mass, possibly coming from the adnexa of the uterus. Preoperative examinations indicated high levels of serum calcium and relevant acute renal dysfunction; hence, continuous renal replacement therapy was performed until all tests reached minimum operation requirements. Interestingly, after excision, serum calcium levels decreased rapidly and therefore, extra calcium had to be taken in order to take the level back up to normal. The patient was diagnosed with OSCCHT based on the clinical data and pathological examinations. After six cycles of chemotherapy, the patient was in a good condition and on follow-up there were no signs of recurrence.

[Diagnostic value of immunohistochemistry and FISH for chromosome 12p in type â ¡ testicular germ cell tumors].

OBJECTIVE: To study the pathological morphology, immunohistochemical characteristics, and molecular changes of type Ⅱ testicular germ cell tumors (TGCT) and investigate the possible value of immunohistochemistry and fluorescence in situ hybridization (FISH) in the diagnosis of TGCT. METHODS: We collected for this study 97 cases of TGCT, including 75 cases of seminoma, 17 cases of embryonal carcinoma, 11 cases of yolk sac tumor, 16 cases of mature teratoma, 3 cases of immature teratoma, and 1 case of epidermoid cyst, in which normal testicular tissue was found in 20 and non-TGCT in 6. We detected the expressions of different antibodies in various subtypes of TGCT by immunohistochemistry and determined the rate of chromosome 12p abnormality using FISH. RESULTS: The immunophenotypes varied with different subtypes of TGCT. SALL4 and PLAP exhibited high sensitivity in all histological subtypes. CD117 and OCT4 showed strongly positive expressions in invasive seminoma and germ cell neoplasia in situ (GCNIS) but not in normal seminiferous tubules. GPC3 was significantly expressed in the yolk sac tumor, superior to GATA3 and AFP in both range and intensity. CKpan, OCT4, and CD30 were extensively expressed in embryonal carcinoma, while HCG expressed in choriocarcinoma. The positivity rate of isochromosome 12p and 12p amplification in TGCT was 96.7% (29/30). CONCLUSIONS: The majority of TGCT can be diagnosed by histological observation, but immunohistochemical staining is crucial for more accurate subtypes and valuable for selection of individualized treatment options and evaluation of prognosis. Chromosome 12p abnormality is a specific molecular alteration in type Ⅱ TGCT, which is useful for ruling out other lesions.

[Embryonal rhabdomyosarcoma in the male reproductive system: A clinicopathological analysis].

OBJECTIVE: To investigate the pathological characteristics, diagnosis, and differential diagnosis of embryonal rhabdomyosarcoma (ERMS) in the male reproductive system. METHODS: We obtained the clinicopathological features, immunophenotypes, and electron microscopic findings of 11 male patients with ERMS in the reproductive system from 2000 to 2015, analyzed the data, and reviewed relevant literature. RESULTS: ERMS developed in these patients at a median age of 17 (9－58) years, 3 cases in the testis, 4 in the scrotum, 1 in the epididymis, and 3 in the prostate. ERMS presented no clinical specificity, which made it difficult to be differentiated from inflammatory and other benign lesions. Microscopically, the tumor cells were arranged in a diffuse or fascicular distribution and mainly composed of short spindle-like, round, or irregularly shaped cells with nuclear hyperchromatism, the cytoplasm strongly eosinophilic, with differentiation of the striated muscle. Some of the cells were naively differentiated or tennis racket-shaped and some exhibited vacuolar degeneration in the cytoplasm. The nuclei were round or short spindle-shaped with visible nucleoli and mitoses. Immunohistochemically, the tumor cells were positive for Myogenin (5/6), Desmin (11/11), MyoD1 (8/9), and Myosin (1/2). Electron microscopy revealed early myofibrils in the cytoplasm of the tumor cells. CONCLUSIONS: ERMS is a rare and highly malignant tumor characterized by local invasion and early metastasis and apt to develop in the reproductive system of young males. The diagnosis of the malignancy is mainly based on its histopathological and immunohistochemical manifestations, combined with electron microscopy when necessary. Early surgical resection in combination with radio- and chemotherapy is recommended for its treatment, which could reduce the recurrence of the tumor and improve the survival of the patients.

PSF/SFPQ is a very common gene fusion partner in TFE3 rearrangement-associated perivascular epithelioid cell tumors (PEComas) and melanotic Xp11 translocation renal cancers: clinicopathologic, immunohistochemical, and molecular characteristics suggesting classification as a distinct entity.

An increasing number of TFE3 rearrangement-associated tumors, such as TFE3 rearrangement-associated perivascular epithelioid cell tumors (PEComas), melanotic Xp11 translocation renal cancers, and melanotic Xp11 neoplasms, have recently been reported. We examined 12 such cases, including 5 TFE3 rearrangement-associated PEComas located in the pancreas, cervix, or pelvis and 7 melanotic Xp11 translocation renal cancers, using clinicopathologic, immunohistochemical, and molecular analyses. All the tumors shared a similar morphology, including a purely nested or sheet-like architecture separated by a delicate vascular network, purely epithelioid cells displaying a clear or granular eosinophilic cytoplasm, a lack of papillary structures and spindle cell or fat components, uniform round or oval nuclei containing small visible nucleoli, and, in most cases (11/12), melanin pigmentation. The levels of mitotic activity and necrosis varied. All 12 cases displayed moderately (2+) or strongly (3+) positive immunoreactivity for TFE3 and cathepsin K. One case labeled focally for HMB45 and Melan-A, whereas the others typically labeled moderately (2+) or strongly (3+) for 1 of these markers. None of the cases were immunoreactive for smooth muscle actin, desmin, CKpan, S100, or PAX8. PSF-TFE3 fusion genes were confirmed by reverse transcription polymerase chain reaction in cases (7/7) in which a novel PSF-TFE3 fusion point was identified. All of the cases displayed TFE3 rearrangement associated with Xp11 translocation. Furthermore, we developed a PSF-TFE3 fusion fluorescence in situ hybridization assay for the detection of the PSF-TFE3 fusion gene and detected it in all 12 cases. Clinical follow-up data were available for 7 patients. Three patients died, and 2 patients (cases 1 and 3) remained alive with no evidence of disease after initial resection. Case 2 experienced recurrence and remained alive with disease. Case 5, a recent case, remained alive with extensive abdominal cavity metastases. Our data suggest that these tumors belong to a single clinicopathologic spectrum and expand the known characteristics of TFE3 rearrangement-associated tumors.

Fibrosarcoma arising from gouty tophi: report of a unique case and review of literature.

Fibrosarcoma is a malignant mesenchymal tumor. To the author's best knowledge, no previous case of fibrosarcoma arising from gouty tophi has been reported. Here we reported the first case of fibrosarcoma arising from gouty tophi. A case of 58-year-old man was presented with a mass with ulcer and infection in the second joint of left middle finger for 2 months, with long standing gouty tophi. The tumor was biopsied and the biopsy showed complete excision of the tumor. With the pathological and immunohistochemical features considered, the diagnosis of fibrosarcoma associated with gouty tophi was made. The clinical findings, pathological characteristics and treatment were described.

Nearly Normal Congenital Cervical Fragmentation: A Hard-To-Diagnose and Successful End-To-End Anastomosis.

BACKGROUND: Congenital cervical fragmentation is a very rare genital tract malformation that usually presents in adolescence with primary amenorrhea and cyclic, monthly, lower abdominal pain. We report a nearly normal case of congenital cervical fragmentation and successful end-to-end anastomosis. CASE: A 15-year-old girl presented with primary amenorrhea with cyclic, monthly lower abdominal pain lasting for 15 months without any abnormal imaging findings (pelvic CT scan, ultrasonography, and hysteroscopy). Misdiagnosis and appendectomy was performed at the time of the initial lower abdominal pain. Diagnostic combined hysteroscopy and laparoscopy were performed in our hospital, and cervical fragmentation was diagnosed. A converted laparotomy end-to-end anastomosis was performed successfully, and regular menstruation was restored after the operation. SUMMARY AND CONCLUSION: The malformation of nearly normal congenital cervical fragmentation is existent and hard to diagnose. As long as the patient has persistent primary amenorrhea with cyclic, monthly lower abdominal pain, even if no abnormal findings on imaging, obstructive malformation of the reproductive duct should be the primary suspicion. Diagnosis and treatment should occur as early as possible to preserve the patient's fertility. End-to-end anastomosis is the best method for this type of patient.

[Papillary cystadenoma of the epididymis: a report of 2 cases and review of the literature].

OBJECTIVE: To study the clinicopathological characteristics of papillary cystadenoma of the epididymis. METHODS: Using routine pathology and immunohistochemistry, we observed the surgically obtained samples from 2 cases of papillary cystadenoma of the epididymis, analyzed their pathological features and clinical presentations, and reviewed the related literature. RESULTS: The 2 patients were both adult males. The tumors typically manifested as painless swelling in the epididymis, with occasionally dull pain and tenesmus in 1 of the cases. Pathologically, the lesions exhibited three morphological features, i. e., dilated ducts and small cysts surrounded by fibrous connective tissue, adenoid papillary hyperplasia into the cysts embraced by fibrovascular stroma, and acidophil substance present in the cysts. Immunohistochemistry showed that the tumors were strongly positive for CK8/18, CK7, and EMA, but negative for CK20, CEA, MC, Calretenin, P53, P63, SMA, VHL, and CD10, with the positive rate of Ki-67 <1%. Follow-up visits revealed good prognosis in both cases. CONCLUSION: Papillary cystadenoma of the epididymis is a rare benign tumor in the male urogenital system, which may be accompanied by the VHL syndrome. Surgery is the first choice for its treatment.

Frequent co-inactivation of the SWI/SNF subunits SMARCB1, SMARCA2 and PBRM1 in malignant rhabdoid tumours.

AIMS: Malignant rhabdoid tumours (MRTs) are highly aggressive malignancies of early infancy characterized by inactivation of SMARCB1, a core member of the SWI/SNF chromatin-remodelling complex. The aim of this study was to explore the status of multiple key subunits of the SWI/SNF complex in MRTs. METHODS AND RESULTS: We screened the key subunits of the SWI/SNF complex, including SMARCB1, SMARCA2, PBRM1, SMARCA4, and ARID1A, in four MRTs by immunohistochemistry, sequencing, and fluorescence in-situ hybridization (FISH). Complete loss of SMARCB1, SMARCA2 and PBRM1 expression and corresponding mutations in the same genes were observed in all cases. The mutations included seven missense, three same-sense, four frameshift and two truncating mutations. FISH revealed heterozygous deletion of SMARCB1 in one case, and monoploidy of chromosome 22, which harbours SMARCB1, in another case. Furthermore, trisomy of chromosome 9, which harbours SMARCA2, was observed in two cases. Abnormality of PBRM1 was not found in any case. CONCLUSIONS: We report, for the first time, co-inactivation and frequent mutations of SMARCB1, SMARCA2 and PBRM1 in MRTs. Multiple subunit abnormalities of the SWI/SNF complex potentially act together to contribute to the tumorigenesis of MRTs, which provides unique insights into this disease.

Perivascular epithelioid cell tumor (PEComa) with TFE3 gene rearrangement: clinicopathological, immunohistochemical, and molecular features.

Perivascular epithelioid cell tumors (PEComas) have been increasingly associated with gene rearrangement of the transcription factor E3 (TFE3). We present three cases of PEComa with a TFE3 gene abnormality detected by immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH). Their clinical features, pathological morphology, and prognosis were investigated. Histologically, the tumors in these three cases showed predominantly epithelioid cells arranged in nests or sheets separated by a delicate vascular network, within two of the three cases nuclear atypia, mitotic figures, and necrosis. All three cases showed strong TFE3 and cathepsin K immunoreactivity and weak to strong reactivity for HMB45. One case of PEComa with TFE3 gene fusion exhibited a benign course. The other two cases of PEComa with both TFE3 translocation and X-chromosome polysomy were histologically malignant and showed aggressive growth. In summary, unusual cases of PEComa with TFE3 gene rearrangement might present malignant histological features and aggressive clinical behavior. Our results add cases to the literature and describe an association of polysomy with aggressive behavior.

Thymidine kinase 1 is a better prognostic marker than Ki-67 for pT1 adenocarcinoma of the lung.

OBJECTIVES: The sensitivity and reliability of the biomarkers thymidine kinase 1 (TK1) and Ki-67 were studied in relation to clinical features and prognosis of survival for pathological-T1 (pT1) lung adenocarcinoma patients. METHODS: TK1 and Ki-67 expression was determined in 80 patients with pT1 adenocarcinoma of the lung and in 20 specimens from normal lung tissues, using immunohistochemistry. RESULTS: TK1 was found in most lung tumor cells both in the cytoplasm and the nuclei. The positive labelling index (LI) for total TK1 was significantly higher than that for Ki-67. There was a significant correlation between the LI of total TK1 and lymph node metastasis, degree of tumor invasion and pathologic stages, which was not found for Ki-67. In addition, the overall 5-year survival of patients was statistically significant different between low and high levels of TK1 expression, but not in cases of Ki-67. A multivariate analysis revealed that expression of TK1, lymph node involvement and TNM pathology staging could serve as independent prognostic factors for the disease progression of pT1 lung adenocarcinoma patients. CONCLUSIONS: Compared with Ki-67, TK1 is a more reliable proliferation index in pT1 adenocarcinoma of lung, which can evaluate the invasion and the prognosis of tumor.

Concurrent loss of INI1, PBRM1, and BRM expression in epithelioid sarcoma: implications for the cocontributions of multiple SWI/SNF complex members to pathogenesis.

The loss of INI1 (SMARCB1) expression, caused by SMARCB1 (INI1, SNF5L4, BAF47) inactivation, frequently occurs in epithelioid sarcoma (ES) and could aid in confirming the diagnosis. Except for INI1, the expression of switch in mating type/sucrose nonfermentation complex members in ES has never been examined. In this study, the expression of key subunits of this complex-INI1, BRG1 (SMARCA4), BRM (SNF2L2, SMARCA2), PBRM1 (hPB1, BAF180), and BAF155 (SMARCC1)-was analyzed in 23 ES cases: 15 conventional and 8 proximal type. All of the cases were reviewed and reclassified by hematoxylin-eosin staining and immunostaining for cytokeratin AE1/3, epithelial membrane antigen, CD34, vimentin, and INI1 expression. Of the 23 ES cases, 19 (82.6%) showed a loss of PBRM1, and 18 (78.3%), a loss of INI1. In most cases (17, 73.9%), loss of INI1 and PBRM1 expression was observed. The pattern of PBRM1 expression was similar to that of INI1, that is, not correlated with changes in cellular morphology. The concurrent loss of BRM, PBRM1, and INI1expression was detected in 2 cases with pure rhabdoid tumor features. The frequent observation of concurrent loss of INI1 and PBRM1 suggests that certain switch in mating type/sucrose nonfermentation complex components might act synergistically in the pathogenesis of ES by unknown mechanisms and that these components could provide new targets for therapy. The usefulness of PBRM1 as a biomarker of ES and its mechanism in ES require further investigation. Loss of BRM in ES with pure rhabdoid features suggests that BRM might be involved in the underlying mechanisms of this type of ES.

[Primary testicular yolk sac tumor: clinicopathological study of 8 cases].

OBJECTIVE: To investigate the clinicopathological characteristics, diagnosis and treatment of primary testicular yolk sac tumor (YST). METHODS: We studied 8 cases of primary testicular YST by microscopy and immunohistochemistry. RESULTS: The 8 cases of primary testicular YST, including 2 consultation cases, were confirmed from 1998 to 2013, accounting for 10.7% (8/75) of all the testicular germ cell tumors diagnosed in our hospital. The patients ranged in age from 7 to 43 years, 23.9 years on average. The main clinical manifestation of the patients was painless unilateral testis swelling. Microscopically, reticular tissues, schiller-duvaI (S-D) bodies, and eosin-stain transparent bodies were seen in the tumors. One of the cases was confirmed to be simple YST, while the other 7 mixed YST. AFP was a characteristic immunophenotype marker of the tumors. CONCLUSION: Primary testicular YST is a rare malignancyr with poor prognosis. Its diagnosis depends on preoperative AFP test and postoperative pathology. Comprehensive treatment, including orchiectomy, chemotherapy, and radiotherapy, can prolong the survival of the patients.

Dysregulation of microRNA biosynthesis enzyme Dicer plays an important role in gastric cancer progression.

BACKGROUND AND AIM: Dicer is one of the most important components in microRNA biogenesis. Although studies have revealed the aberrantly expression of Dicer in types of cancer, the results were greatly controversial. Here we aimed to study the expression of Dicer in gastric cancer (GC) and further explored the possible roles of Dicer in cancer progression. METHODS: The alteration of Dicer-expression in GC and its clinical significance was retrospectively studied with immunohistochemical analyses on 377 cases of cancer tissues using tissue microarray (TMA). Dicer mRNA and protein levels were also examined in 8 paired of GC tissues and non-neoplastic surrounding gastric epithelium with real time RT-PCR and western blot. RESULTS: We found that Dicer was reduced in GC tissues in both mRNA and protein levels. Moreover, down-regulation of Dicer was correlated highly with tumor differentiation (P<0.05) and lymph node invasion (P<0.05) in GC tissues, which suggested an essential role of Dicer in cancer invasion. CONCLUSIONS: Considering that Dicer might be closely related to progression of GC, we proposed that Dicer might offer a promising target for prevention of metastatic progression in GC.

Coexistent loss of INI1 and BRG1 expression in a rhabdoid renal cell carcinoma (RCC): implications for a possible role of SWI/SNF complex in the pathogenesis of RCC.

In this study, we analyzed the immunohistochemical and molecular profiles of an unusual RCC showed coexistent absence of INI1 and BRG1 expression, rhabdoid morphology, and poor prognosis. Histologically, the tumor had rhabdoid features, which were demonstrated by large round to polygonal cells with eccentric nuclei, prominent nucleoli, and eosinophilic cytoplasm varying from abundant to scanty. Immunohistochemically, the tumor were positive for BRM, PBRM1, ARID1A, CD10, CKpan, Vimentin, carbonic anhydrase IX (CA-IX), and P504S (AMACR) but negative for INI1, BRG1, HMB45, melan A, CK7, CD117, Ksp-cadherin, TFEB, TFE3, and Cathepsin K. We detected all three exons status of the VHL gene of the tumor and observed 1 somatic mutations in 1st exon. Chromosome 3p deletion, coupled with polysomy of chromosome 3 was also found. Based on these findings, it is further indicated that in some cases, rhabdoid RCC may arise from clear cell RCC. SWI/SNF chromatin remodeling complex may be an attractive candidate for being the "second hit" in RCCs and may play an important role during tumor progression. The role of SWI/SNF complex in rhabdoid RCC should be further studied on a larger number of cases.

Cathepsin K in the immunohistochemical diagnosis of melanocytic lesions.

Recent studies have demonstrated that cathepsin K seems to be a powerful marker in identifying the microphthalmia associated transcription factor (MITF) family tumors such as renal perivascular epithelioid cell neoplasms (PEComas), alveolar soft part sarcoma, and translocation-associated renal cell carcinomas. However, the expression of cathepsin K in melanocytic lesions has not been well characterized. Our aim was to investigate the expression of cathepsin K in a wide histological spectrum of melanocytic lesions and to evaluate its potential diagnostic and molecular target therapy usefulness in comparison with other commonly used markers. 143 consecutive melanocytic lesions were selected for study including 56 primary malignant melanomas, 62 metastatic melanomas, and 25 benign nevi (16 intradermal melanocytic nevi and 9 compound melanocytic nevi). 107 of the 118 (91%) primary and metastatic melanomas displayed a high percentage of cells with moderately to strongly positive reactions for cathepsin K (mean 82%; range 0-95%). MITF, HMB45, Melan-A, and S100 were expressed in 85, 76, 78 and 96% of cases, respectively, with various percentages of positive cells (mean, 63, 49, 55 and 86%; range 0-90, 0-80, 0-90 and 0-95%). Among the benign nevi, cathepsin K, MITF, HMB45, Melan-A, and S100 were expressed in 88, 80, 36, 68 and 100% of cases, respectively. Cathepsin K appears to be consistently and strongly expressed in melanocytic lesions and valuable in distinguishing malignant melanomas from the majority of human cancers.