Wen-Wei Huang

Skp2 is an independent prognosticator of gallbladder carcinoma among p27(Kip1)-interacting cell cycle regulators: an immunohistochemical study of 62 cases by tissue microarray.

Despite improvement in surgical techniques, prognosis of gallbladder carcinoma remains poor. It is desirable to identify prognostic biomarkers to aid in the development of targeted therapeutic strategies. Two SCFSkp2 ubiquitin ligase-related proteins, Skp2 and cyclin-dependent kinase subunit 1 (Cks1), are involved in post-transcriptional degradation of p27Kip1 tumor suppressor, which inhibits both cdk2/cyclin E and cdk2/cyclin A complexes and thus prevents transition to the S phase. However, the prognostic utility of p27Kip1-interacting cell cycle regulators has not been systematically assessed in gallbladder carcinoma. Immunohistochemistry was performed for p27Kip1, Skp2, Cks1, cyclin E, cyclin A, and Ki-67 in tissue microarrays of 62 gallbladder carcinomas with follow-up. The data were correlated with clinicopathological features and overall survival (OS). The cumulative OS rate for all 62 cases was 42.9% at 3 years. Aberrant labeling indices (LIs) of p27Kip1 (<20%), cyclin E (≥5%), cyclin A (≥5%), Cks1 (≥40%), and Skp2 (≥10%) were identified in 29, 58, 66, 21, and 57% of gallbladder carcinomas, respectively. By log-rank tests, downregulation of p27Kip1 (P=0.0319) and high LIs of Skp2 (P=0.0006), Cks1 (P=0.0460), cyclin E (P=0.0070), and Ki-67 (P=0.0037) were predictive of inferior OS. Furthermore, the combined expression status of Skp2 and Ki-67 robustly defined three prognostically different groups (P=0.0001). In multivariate comparison, Skp2 overexpression represented the strongest independent adverse prognosticator (P=0.004, risk ratio (RR): 5.538), followed by Ki-67 LI ≥50% (P=0.016, RR: 3.254) and American Joint Committee on Cancer stages II–IV (P=0.013, RR: 3.163). In conclusion, aberrations of p27Kip1-interacting cell cycle regulators are common in gallbladder carcinomas. Skp2 overexpression is highly representative of biological aggressiveness and independently associated with poor OS, suggesting that it is a promising novel target for therapeutic intervention in aggressive cases. The combined assessment of Skp2 and Ki-67 LIs effectively risk-stratifies gallbladder carcinomas with different prognosis, which is worth being prospectively validated in future study.

Heat Shock Protein 90 Overexpression Independently Predicts Inferior Disease-Free Survival with Differential Expression of the α and β Isoforms in Gastrointestinal Stromal Tumors

Purpose: Most gastrointestinal stromal tumors harbor a mutated KIT or PDGFRA receptor tyrosine kinase (RTK). Heat shock protein 90 (Hsp90) is a chaperone mediating the folding and stabilization of many oncoproteins, including KIT. An Hsp90 inhibitor, 17-AAG, can attenuate KIT activation and proliferation of gastrointestinal stromal tumor cell lines. We further evaluated Hsp90 immunoexpression and the difference between α and β isoforms in gastrointestinal stromal tumor specimens. Experimental Design: Hsp90 immunostain was assessable in 306 cases on tissue microarrays of primary gastrointestinal stromal tumors and correlated with various variables and disease-free survival (DFS). RTK mutation variants, confirmed in 142 cases by sequencing with or without precedent denaturing high pressure liquid chromatography screening, were dichotomized into two prognostically different groups. Differential expression of transcript and protein isoforms was measured by real-time reverse transcription-PCR and Western blotting in 16 and 6 cases, respectively. Results: Hsp90 overexpression (55%) significantly correlated with larger size, nongastric location, higher mitotic count and NIH risk level, Ki-67 overexpression (all P ≤ 0.001), and unfavorable RTK genotypes (P = 0.020). It strongly portended inferior DFS univariately (P < 0.0001) and remained independent in multivariate analysis (P = 0.031; risk ratio, 2.44), along with high-risk category, Ki-67 overexpression, and old age. For both mRNA and protein, Hsp90β was more abundant than Hsp90α, whereas the latter was significantly higher in high-risk cases. Conclusions: Hsp90 overexpression represents a poor prognosticator that correlates with several adverse parameters, highlighting its role in disease progression and alternative therapy for high-risk, imatinib-resistant gastrointestinal stromal tumors. Hsp90α seems more relevant to the intrinsic aggressiveness of gastrointestinal stromal tumors, albeit less abundant than Hsp90β.

Malignant diffuse-type tenosynovial giant cell tumors: a series of 7 cases comparing with 24 benign lesions with review of the literature.

Background Malignant diffuse-type tenosynovial giant cell tumor (D-TSGCT), an unusual sarcoma with concurrent or previous benign D-TSGCTs, poses challenges to diagnosis and prognostication. Methods We described the radiologic, clinicopathologic, and immunophenotypical findings of 5 primary and 2 metachronous malignant D-TSGCTs and reviewed published cases to better delineate their morphologic spectrum and behavior. Twenty-four benign D-TSGCTs were also statically compared to analyze the diagnostic values of various variables. Results The 7 malignant cases affected 4 females and 3 males aged 45 to 78 (mean, 60.9) years, which included 1 intra-articular and 6 extra-articular lesions. These tumors were 5 to 17 cm (mean, 9.4) and located within or near the large joints of extremities. Magnetic resonance imaging revealed expansile or infiltrative masses with frequent lobulation and heterogeneous signals. Histologically, areas of benign D-TSGCTs blended abruptly or gradually with frank sarcomas composed of pleomorphic, spindle, or enlarged oval cells, forming malignant fibrous histiocytomalike (n=4), fibrosarcomatous (n=1), myxosarcomatous (n=1), or giant cell tumorlike (n=1) patterns. One patient experienced recurrences twice, and another 3 developed metastases to the lymph nodes (n=2), lung (n=1), or vertebrae (n=1), with 1 dying from disseminated diseases. An older age (P=0.003), a larger size (P=0.036), tumor necrosis (P<0.001), atypical mitoses (P<0.001), and Ki-67 overexpression (P<0.001) appeared preferentially in malignant lesions, but these parameters had overlap between few benign and malignant tumors. Conclusions Malignant D-TSGCTs are a distinct sarcoma with considerable morphologic variability, metastatic propensity, and lethality. Altered architecture with anaplastic cells represents an important distinguishing feature, while abnormalities of other parameters should not be directly equated with malignancy.

Homozygous Deletion of MTAP Gene as a Poor Prognosticator in Gastrointestinal Stromal Tumors

Purpose: Chromosome 9 is frequently deleted in high-risk gastrointestinal stromal tumors (GISTs), whereas its specific tumor suppressor genes (TSGs) are less understood. We did an integrative study of MTAP gene at 9p21 to analyze its implication in GISTs. Experimental Design: To search TSGs on chromosome 9, we used ultrahigh-resolution array comparative genomic hybridization to profile DNA copy number alterations of 22 GISTs, with special attention to MTAP gene. MTAP immunoexpression was assessable for 306 independent GISTs on tissue microarrays, with 146 cases analyzed for MTAP homozygous deletion, 181 for mutations of KIT and PDGFRA receptor tyrosine kinase genes, and 7 for MTAP hypermethylation. Results: Array comparative genomic hybridization identified 11 candidate TSGs on 9p and six on 9q. MTAP and/or CDKN2A/CDKN2B at 9p21.3 were deleted in one intermediate-risk (11) and seven high-risk (70) GISTs with two cases homozygously codeleted at both loci. MTAP homozygous deletion, present in 25 of 146 cases, was highly associated with larger size and higher mitotic rate, Ki-67 index, and risk level (all P < 0.01) but not with receptor tyrosine kinase genotypes. Whereas MTAP homozygous deletion correlated with MTAP protein loss (P < 0.001), 7 of 30 GISTs without MTAP expression did not show homozygous deletion, including three MTAP-hypermethylated cases. MTAP homozygous deletion was univariately predictive of decreased disease-free survival (P < 0.0001) and remained multivariately independent (P = 0.0369, hazard ratio = 2.166), together with high-risk category (P < 0.0001), Ki-67 index >5 (P = 0.0106), and nongastric location (P = 0.0416). Conclusions:MTAP homozygous deletion, the predominant mechanism to deplete protein expression, is present in 17 of GISTs. It correlates with important prognosticators and independently predicts worse outcomes, highlighting the role in disease progression. (Clin Cancer Res 2009;15(22):696372)

Ezrin overexpression in gastrointestinal stromal tumors: an independent adverse prognosticator associated with the non-gastric location

Ezrin, a member of the ezrin–radixin–moesin family, acts as a link between the cell membrane and actin cytoskeleton to integrate cell adhesion-mediated signaling. It implicates tumor progression, metastatic dissemination, and adverse outcomes in several cancer types, including pediatric and adult sarcomas. Although ezrin upregulation was shown by cDNA expression profiling, no study has systematically evaluated the significance of ezrin expression in a large cohort of gastrointestinal stromal tumors (GISTs). Ezrin immunostaining was carried out on tissue microarrays of primary GISTs and assessable in 347 cases, 188 of which were successfully evaluated for mutation variants of KIT and PDGFRA receptor tyrosine kinase (RTK) genes by sequencing with or without screening by denatured high-performance liquid chromatography. These GISTs with known RTK genotypes were dichotomized into two prognostically different groups. The endogenous expression and phosphorylation of ezrin in GIST cell lines were analyzed by western blotting. By immunohistochemistry, ezrin overexpression was present in 66% of GISTs and significantly associated with the non-gastric location (P=0.002) and decreased disease-free survival (P=0.032, univariately). However, it was not related to the National Institute of Health (NIH) risk category, Ki-67 labeling index, RTK genotypes, and other variables. In multivariate analyses, ezrin overexpression remained independently predictive of adverse outcome (P=0.008, risk ratio=2.363), together with Ki-67 labeling index >5% (P<0.001, risk ratio=3.581), high-risk category (P<0.001, risk ratio=2.156), and the non-gastric location (P=0.029, risk ratio=1.899). Despite the variation in the ezrin expression level, phosphorylated ezrin at threonine567 was only detectable in GIST882 and GIST48 cells, but not in colonic smooth muscle cells. In conclusion, ezrin is frequently overexpressed in GISTs, especially those arising from the non-gastric sites. Given that its impact is independent of the NIH risk category, cell proliferation, and tumor location, ezrin immunoreactivity represents a valuable prognostic adjunct of GISTs, suggesting a causative role in conferring an aggressive phenotype.

Immunohistochemical and Biogenetic Features of Diffuse-Type Tenosynovial Giant Cell Tumors: The Potential Roles of Cyclin A, P53, and Deletion of 15q in Sarcomatous Transformation

Purpose: Diffuse-type tenosynovial giant cell tumor (D-TSGCT) is an aggressive proliferation of synovial-like mononuclear cells with inflammatory infiltrates. Despite the COL6A3-CSF1 gene fusion discovered in benign lesions, molecular aberrations of malignant D-TSGCTs remain unidentified. Experimental Design: We used fluorescent in situ hybridization and in situ hybridization to evaluate CSF1 translocation and mRNA expression in six malignant D-TSGCTs, which were further immunohistochemically compared with 24 benign cases for cell cycle regulators involving G1 phase and G1-S transition. Comparative genomic hybridization, real-time reverse transcription-PCR, and a combination of laser microdissection and sequencing were adopted to assess chromosomal imbalances, cyclin A expression, and TP53 gene, respectively. Results: Five of six malignant D-TSGCTs displayed CSF1 mRNA expression by in situ hybridization, despite only one having CSF1 translocation. Cyclin A (P = 0.008) and P53 (P < 0.001) could distinguish malignant from benign lesions without overlaps in labeling indices. Cyclin A transcripts were more abundant in malignant D-TSGCTs (P < 0.001). All malignant cases revealed a wild-type TP53 gene, which was validated by an antibody specifically against wild-type P53 protein. Chromosomal imbalances were only detected in malignant D-TSGCTs, with DNA losses predominating over gains. Notably, −15q was recurrently identified in five malignant D-TSGCTs, four of which showed a minimal overlapping deletion at 15q22-24. Conclusions: Deregulated CFS1 overexpression is frequent in malignant D-TSGCTs. The sarcomatous transformation involves aberrations of cyclin A, P53, and chromosome arm 15q. Cyclin A mRNA is up-regulated in malignant D-TSGCTs. Non–random losses at 15q22-24 suggest candidate tumor suppressor gene(s) in this region. However, P53 overexpression is likely caused by alternative mechanisms rather than mutations in hotspot exons.

Electronic barometric altimeter in real time correction

The barometric altitude measurement using modern electronic sensors has significant error due to atmospheric pressure variations with respective to weather and time. Based on the altimeter setting concept, the barometric altimeter should be corrected according to hourly QNH data to maintain accuracy. This paper presents an airborne altitude measurement technology using barometric measurement and real time calibration through GPRS uplink. The proposed method is practical in correcting the time variant error of the electronic barometric altimeter automatically. After these corrections, the static and dynamic accuracy of the electronic barometric altimeter can be much improved into less than 2% errors in real time. The proposed system is suitable for ultra light aircrafts (ULA) or unmanned aerial vehicles (UAV).