Frequency and features of TP53 mutation in 30 Chinese patients with sporadic basal cell carcinoma

BACKGROUND

Basal cell carcinoma (BCC) is a prevalent form of nonmelanoma skin cancer. Although numerous studies in white populations suggest that mutations in the TP53 gene play an important role in the development of BCC, it is not clear whether this is also the case in East Asian populations such as in China.

AIM

To investigate the frequency and the features of TP53 mutation in sporadic BCC in a Chinese population.

METHODS

In total, 30 patients with sporadic BCC, who had previously taken part in a study on PTCH1 mutations, were enrolled. BCC and control cells were obtained by laser-capture microdissection, and DNA was amplified and sequenced for analysis of TP53 mutations.

RESULTS

In the 30 BCC samples, 6 TP53 point mutations were found (frequency of 20%), and 4 of these 6 mutations had ultraviolet (UV)-specific alterations. Combining these results with those of the previous study on PTCH1 mutations, we found that two patients with had three types of genetic alterations (each had two PTCH1 mutations and one TP53 point mutation). A further two patients each had one PTCH1 mutation and one UV signature TP53 mutation. In addition, the total number of UV-specific mutations of PTCH1 and TP53 accounted for 20% of the total patient group.

CONCLUSIONS

The incidence of TP53 mutation in BCC in our Chinese subjects was lower than that reported for white populations. Many of the patients carried mutations of other genes in addition to of TP53. The majority of TP53 mutations were UV-induced specific alterations. However, the results of the two studies on TP53 and PTCH1 indicated that the incidence of UV-specific mutations is much lower in Chinese than in white populations.

Malignant perivascular epithelioid cell tumor (PEComa) of cervix with TFE3 gene rearrangement: a case report

In this study, we reported the first PEComa arising within the cervix with TFE3 gene rearrangement and aggressive biological behavior. Morphologically, the tumor showed infiltrative growth into the surrounding parenchyma. The majority of tumor cells were arrayed in sheets, alveolar structures, or nests separated by delicate fibrovascular septa. There was marked intratumoral hemorrhage, necrosis, and stromal calcifications. The tumor cells had abundant clear cytoplasm, focally containing finely granular dark brown pigment, morphologically considered to be melanin. Immunohistochemically, the tumor cells demonstrated moderately (2+) or strongly (3+) positive staining for TFE3, HMB45, and Melan A but negative for CKpan, SMA, S100, PAX8, and PAX2. The presence of Ki-67 protein demonstrated a moderate proliferation rate, with a few Ki-67-positive nuclei. Using a recently developed TFE3 split FISH assay, the presence of TFE3 rearrangement was demonstrated. All these clinicopathologic features are suggestive of TFE3-rearranged PEComas of the cervix. Our results both expand the known characteristics of primary cervix PEComas and add to the data regarding TFE3 rearrangement-associated PEComas.

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.

Clear cell papillary renal cell carcinoma: a clinicopathological study emphasizing ultrastructural features and cytogenetic heterogeneity

Clear cell papillary renal cell carcinoma (CCPRCC) is a recently recognized renal neoplasm, which was initially described in end-stage renal disease (ESRD), but some cases have been reported in otherwise normal kidneys. We report a series of 11 CCPRCC (age range, 33-72 years; male-to-female ratio, 8:3). Follow-up was available for 8 patients. No patients developed local recurrence, distant or lymph-node metastasis, or cancer death. Histologically, all tumors exhibit morphologic features typical of CCPRCC including a mixture of cystic and papillary components, covered by small to medium-sized cuboidal cells with abundant clear cytoplasm. All 11 cases exhibited moderate to strong positivity for CK7, CA9, Vim, and HIF-1α, coupled with negative reactions for CD10, P504S, and RCC. We did not find any VHL gene mutations in all 11 cases. Losses of chromosomes 3 (monoploid chromosome 3) was detected in 3 cases. Ultrastructurally, the tumor cells composed of numerous glycogens with scanty cell organelles, reminiscent of clear cell renal cell carcinoma (CCRCC). In conclusion, the coexpression of CA9 and HIF-1α in the absence of VHL gene abnormalities in CCPRCC suggests activation of the HIF pathway by mechanisms independent of VHL gene mutation. Losses of chromosomes 3 (monosomies chromosome 3) was detected in 3 cases suggesting that at least some of these lesions have demonstrated abnormalities of chromosomes 3. Ultrastructurally, CCPRCC composed of numerous glycogens with scanty cell organelles, reminiscent of CCRCC suggesting the close pathogenesis relationship of CCPRCC with CCRCC.

[Immunohistochemical study of perivascular epithelioid cell neoplasms]

OBJECTIVE

To study the clinicopathologic features, immunophenotype and genetic changes of perivascular epithelioid cell neoplasms (PEComa).

METHODS

A total of 25 cases of PEComa located in various anatomic sites were selected for immunohistochemical staining (SP or EnVision method). TFE3 fluorescence in-situ hybridization was also performed to determine the TFE3 gene status.

RESULTS

The age of patient ranged from 21 to 61 years (mean = 43 years). The male-to-female ratio was 1: 1.3. Histologically, 22 cases represented conventional angiomyolipomas, composed of a mixture of adipose tissue, spindle element, epithelioid smooth muscle cells and abnormal thick-walled blood vessels in various proportions. Three cases involving lung, soft tissue and broad ligament had subtle but distinctive morphologic features. Nested or sheet-like architecture with epithelioid or spindle cells was observed. Immunohistochemical study showed that HMB 45, melan A, smooth muscle actin and cathepsin K were expressed in 80% (20/25), 88% (22/25), 88% (22/25) and 100% (25/25) of PEComa, respectively. Within positive cases, the average proportion of positive tumor cells was 36%, 41%, 35% and 90% respectively for HMB 45, melan A, smooth muscle actin and cathepsin K. TFE3 was negative in all of the 22 renal and hepatic PEComa studied, while it was positive in the 3 cases of extra-hepatorenal PEComa. None of the 25 cases exhibited evidence of TFE3 gene fusion or amplification.

CONCLUSIONS

Extra-hepatorenal PEComa have distinctive morphologic features and are associated with TFE3 overexpression. Cathepsin K immunostaining demonstrates high sensitivity and specificity in PEComa, better than other commonly employed immunomarkers. This marker is thus useful in diagnosis of PEComa and distinction with other neoplasms.

Sporadic hemangioblastoma of the kidney with PAX2 and focal CD10 expression: report of a case

In this study, we presented an additional case of renal hemangioblastoma, which demonstrates PAX2 and focal CD10 expression. Histologically, the tumor consisted of sheets of oval or polygonal cells and a prominent vascular network. The tumor cells varied in size, and possessed pale or eosinophilic cytoplasm that sometimes contained sharply delineated fine vacuoles. The tumor cell nuclei with inconspicuous nucleoli showed moderate nuclear atypia and pleomorphism. Focal areas of stromal hyalinization and sclerosis were detected. On account of its strong or moderate immunoreactivity for the a-inhibin, S100, NSE, and EGFR, the diagnosis of renal hemangioblastoma was established. For further evidence of VHL deficiency, the tumor was subjected to VHL sequence analysis of all three exons and fluorescence in situ hybridization (FISH) detection for chromosome 3p deletion. None of the VHL gene mutations and chromosome 3p deletion was detected in the tumor. Because of several shared morphological and immunophenotypic features, renal hemangioblastoma may be underrecognized and should be included in the differential diagnosis of primary renal tumors, in particular clear cell renal cell carcinoma. The unexpected positive staining of PAX2 and CD10 in renal hemangioblastoma should be particular concerned. Using a combination of immunoprofile may be helpful to the differential diagnosis of these renal tumors.

Renal cell carcinomas with t(6;11)(p21;q12) presenting with tubulocystic renal cell carcinoma-like features

In this study, we reported an additional genetically confirmed case of renal cell carcinomas (RCCs) with t(6;11)(p21;q12) showing an unusual histological pattern. Histologically, the tumor was entirely composed of small to intermediate sized tubules and cysts. The tubules and cysts were lined by a single layer of flat, hobnail, cuboidal to columnar epithelial cells. Most cells demonstrated abundant eosinophilic cytoplasm with regular, round or oval nuclei and some inconspicuous nucleoli. All these morphological features are suggestive of tubulocystic carcinoma of the kidney. However, the tumor demonstrated moderately (2+) or strongly (3+) positive staining for TFEB, Cathepsin K, Ksp-cadherin, and vimentin but negative for TFE3, CD10, HMB45, melan A, CKpan, and CK7. Using a recently developed TFEB split FISH assay, the presence of TFEB rearrangement was demonstrated. Our results support the clinical application of a TFEB break-apart FISH assay for diagnosis and confirmation of TFEB RCC and further expand the morphologic spectrum that may be present in these neoplasms, sometimes raising a challenging differential diagnosis with other renal tumors.

Cathepsin K expression in a wide spectrum of perivascular epithelioid cell neoplasms (PEComas): a clinicopathological study emphasizing extrarenal PEComas

AIMS

Recent studies have demonstrated that cathepsin K seems to be a powerful marker in identifying renal perivascular epithelioid cell neoplasms (PEComas). However, the expression in extrarenal PEComas has not been well characterized due to their rare incidence. Our aim was to investigate the expression of cathepsin K in a wide spectrum of extrarenal PEComas and evaluate its potential diagnostic usefulness in comparison with other commonly used markers.

METHODS AND RESULTS

Twenty-three cases of PEComa (liver, n = 9; lung, n = 1; broad ligament of uterus, n = 1; vertex subcutaneous soft tissue, n = 1; abdominal wall, n = 1; and kidney, n = 10) were selected for study. All displayed a high percentage of cells with moderately to strongly positive reactions for cathepsin K (mean 91%; range 80-100%). HMB45, Melan-A and smooth muscle actin (SMA) were expressed in 78, 87 and 87% of cases, respectively, with various percentages of positive cells (mean, 34, 40 and 38%; range 0-80, 0-90 and 0-90%). Transcription factor E3 (TFE3) was expressed strongly in only three cases; none exhibited evidence of TFE3 gene fusion or amplification.

CONCLUSIONS

Cathepsin K appears to be more powerful than other commonly used markers in diagnosing a wide spectrum of PEComas and distinguishing them from the majority of human cancers.

Effect of three polyether ionophores on pharmacokinetics of florfenicol in male broilers

Drug-drug interactions (DDIs) may adversely affect the prevention and cure of diseases. The effects of three polyether ionophore antibiotics, salinomycin (SAL), monensin (MON), and maduramycin (MAD) on the pharmacokinetics of florfenicol (FFC) were investigated in broilers. The chickens were fed rations with or without SAL (60 mg/kg feeds), MON (120 mg/kg feeds), or MAD (5 mg/kg feeds) for 14 consecutive days. FFC was given to the chickens either intravenously (i.v.) or orally (p.o.) at a single dose of 30 mg/kg body weight. Blood samples were taken from each chicken at 0-24 h postadministration of FFC. The plasma concentration of FFC was detected by high-performance liquid chromatography. The plasma concentration of FFC decreased with i.v. or p.o. co-administration of SAL, MON, or MAD in broilers, implying occurrence of DDIs during the co-administration of FFC with these ionophores. Our findings suggest that more attention should be given to the use of FFC to treat bacterial infections in chickens supplemented with polyether ionophore antibiotics.

Distinguishing urothelial carcinoma in the upper urinary tract from benign diseases with hematuria using FISH

OBJECTIVE

The aims of this study were to evaluate the clinical utility of a fluorescence in situ hybridization (FISH) assay as a non-invasive molecular test to distinguish urothelial carcinoma (UC) in the upper urinary tract (UUT) from benign lesions presenting with hematuria.

STUDY DESIGN

The chromosomal abnormalities of chromosomes 3, 7, 17 and 9 (p16) in hematuria specimens from 34 patients with UUT-UC and 33 patients with benign disorders were detected using a set of fluorescently labeled DNA probes. The abnormalities of the chromosomes were determined and analyzed between UUT-UC and benign disorders.

RESULTS

Chromosomal abnormalities were detected in 25 of 34 (73.5%) patients with UUT-UC and in 2 of 33 (6.1%) patients with benign disorders (p < 0.001).

CONCLUSIONS

FISH of chromosomes 3, 7, 9 and 17 performed on exfoliated cells from voided urine specimens may serve as a non-invasive tool to distinguish UUT-UC from benign disorders presenting with hematuria.

Unique features of PTCH1 mutation spectrum in Chinese sporadic basal cell carcinoma

BACKGROUND

Alterations of the PTCH1 gene have been found to contribute to both familial and sporadic basal cell carcinoma (BCC), especially in Caucasian patients. Furthermore, the majority of PTCH1 gene mutations in sporadic BCCs in Caucasian patients carry ultraviolet (UV) signatures, suggesting the key role of UV light in BCC development. However, sporadic BCC in non-Caucasian population has a lower incidence, and the pathogenesis remains largely unknown. To date, there has been no mutation analysis on PTCH1 gene in Chinese patients with sporadic BCCs.

OBJECTIVE

To investigate genetic alterations of the PTCH1 gene in Chinese sporadic BCCs.

METHODS

Direct sequencing was used to screen for mutations in PTCH1 in 31 microdissected samples in Chinese sporadic BCCs. In addition, single nucleotide polymorphisms (SNPs) were studied for loss of heterozygosity (LOH).

RESULTS

Nineteen PTCH1 mutations in 17 of the 31 BCCs (54.8%) were identified. SNP analysis revealed LOH of PTCH1 in 10 of 23 BCCs (43.5%). Interestingly, the majority of mutations identified (63.2%) were insertion/deletion, which was different from the results in Caucasian cases whose mutations are predominantly point mutations. Only two (10.5%) of the remaining seven mutations were UV-specific C → T transition or tandem CC → TT transitions. All mutations occurred evenly throughout the entire PTCH1 protein domain without a hot-spot detected.

CONCLUSION

Mutations and LOH in PTCH1 were also highly prevalent in Chinese sporadic BCCs. However, UV light plays a less role in causing these mutations, suggesting other potential mechanisms in the development of sporadic BCC in Chinese patients.

[Ultrastructural changes of hepatocyte fibrogenesis in cholelithiasis]

OBJECTIVE

To explore the ultrastructural changes of hepatocyte fibrogenesis in cholelithiasis in biliary tract.

METHODS

l0 liver biopsies were taken from the patients suffered from gallstone and choledocholithiasis during surgical treatment and the ultrastructural changes were observed under electromicroscope.

RESULTS

There were plentiful collagenous microfibrils (CMFs) grown within some hepatocytes. These CMFs distributed locally or diffusely in cytoplasm even extended into nucleus. In 7 cases numerous megamitochondrias appeared in several hepatocytes, the inclusions mimicking fibrils could be frequently seen and grew beyond the envelope. Furthermore, typical CMFs could be seen in the large microbodies, and several vesicular or cystic structures similar as fibroblast were presented in marginal areas of the hepatocytes.

CONCLUSIONS

We deduce that the fibrosed hepatocytes may be remained and take part in the hyperplasia of hepatic fibrous tissue.

Tenuifolin, an extract derived from tenuigenin, inhibits amyloid-beta secretion in vitro

AIM

Previous studies have shown that tenuigenin, a crude extract of Polygala tenuifolia Willd. that is commonly used in traditional Chinese herbal medicine for memory loss, can reduce the secretion of Abeta from cultured cells. However, the mechanism underlying this effect and the active compound derived from tenuigenin is unknown. In this study, a purified component of tenuigenin, tenuifolin, was examined and revealed to be an effective compound in vitro.

METHODS

Abeta secretion from three sets of COS-7 cells, each carrying a plasmid expressing a different form of APP was examined following the treatment with tenuifolin. Initially, tenuifolin was determined to have no inherent toxicity to either the transfected or wild type cells at the effective concentrations. Cells were then treated with 0.5-2.0 microg mL(-1) tenuifolin for 12 h and their media were examined via an ELISA for Abeta1-40 and Abeta-42.

RESULTS

We found that treatment with 2.0 microg mL(-1) tenuifolin significantly decreased Abeta secretion from COS-7 cells without altering the ratio of Abeta1-40 and Abeta-42. This effect is most probably due to inhibition of the beta-site APP cleaving enzyme as Abeta secretion was not inhibited from cells expressing the C99 fragment.

CONCLUSION

Tenuifolin is an effective compound from tenuigenin. We believe that this finding should lead the way for future experiments to determine the exact mechanism for tenuifolin's effect on Abeta secretion.