Sandra Lee

The synaptic vesicle protein SV2 is a novel type of transmembrane transporter

The primary function of synaptic vesicles is to store and release neurotransmitter. Synaptic vesicles are locally recycled following exocytosis and rapidly refilled with neurotransmitter from the cytoplasm by a process that depends on the electrochemical gradient generated by a proton pump. Little is known about the molecules that import neurotransmitter into synaptic vesicles. We report here that the sequence of the synaptic vesicle protein SV2 identifies this protein as a novel type of transmembrane transporter. The deduced amino acid sequence of SV2 contains two sets of six predicted transmembrane domains: the six most N-terminal transmembrane domains are highly homologous to a subfamily of transporters that includes the human glucose transporter, while the six most C-terminal domains are homologous to the plasma membrane transporters for neurotransmitters. We propose that SV2 mediates transport of neurotransmitters into synaptic vesicles.

Spectrophotometric determination of oxidized and reduced pyridine nucleotides in erythrocytes using a single extraction procedure.

Several methods are available for the extraction and quantitation of oxidized and reduced pyridine nucleotides in erythrocytes. Enzymatic methods, however, are complicated by the presence of hemoglobin, which causes oxidation of NADH and NADPH during extraction. Although hemoglobin-mediated oxidation can be prevented by the addition of reducing agents, these interfere with spectrophotometric cycling assays for these nucleotides. Therefore, we have developed a method for determining oxidized and reduced NAD and NADP in human erythrocytes using a single extract. Our extraction method eliminates the need for reducing agents and thus allows the use of a spectrophotometric cycling assay. Using this method, we obtained full recovery of all added nucleotides with both normal and reticulocyte-enriched red blood cells. Our method is suitable for the determination of NAD+, NADH, NADP+, and NADPH in normal human erythrocytes and in red cells from patients with hemolytic anemia with a higher proportion of reticulocytes.

Biomarker-Based Ovarian Carcinoma Typing: A Histologic Investigation in the Ovarian Tumor Tissue Analysis Consortium

Background: Ovarian carcinoma is composed of five major histologic types, which associate with outcome and predict therapeutic response. Our aim was to evaluate histologic type assessments across the centers participating in the Ovarian Tumor Tissue Analysis (OTTA) consortium using an immunohistochemical (IHC) prediction model. Methods: Tissue microarrays (TMA) and clinical data were available for 524 pathologically confirmed ovarian carcinomas. Centralized IHC was conducted for ARID1A, CDKN2A, DKK1, HNF1B, MDM2, PGR, TP53, TFF3, VIM, and WT1, and three histologic type assessments were compared: the original pathologic type, an IHC-based calculated type (termed TB_COSPv2), and a WT1-assisted TMA core review. Results: The concordance between TB_COSPv2 type and original type was 73%. Applying WT1-assisted core review, the remaining 27% discordant cases subdivided into unclassifiable (6%), TB_COSPv2 error (6%), and original type error (15%). The largest discordant subgroup was classified as endometrioid carcinoma by original type and as high-grade serous carcinoma (HGSC) by TB_COSPv2. When TB_COSPv2 classification was used, the difference in overall survival of endometrioid carcinoma compared with HGSC became significant [RR 0.60; 95% confidence interval (CI), 0.37–0.93; P = 0.021], consistent with previous reports. In addition, 71 cases with unclear original type could be histologically classified by TB_COSPv2. Conclusions: Research cohorts, particularly those across different centers within consortia, show significant variability in original histologic type diagnosis. Our IHC-based reclassification produced more homogeneous types with respect to outcome than original type. Impact: Biomarker-based classification of ovarian carcinomas is feasible, improves comparability of results across research studies, and can reclassify cases which lack reliable original pathology. Cancer Epidemiol Biomarkers Prev; 22(10); 1677–86. ©2013 AACR.

An Immunohistochemical Algorithm for Ovarian Carcinoma Typing.

There are 5 major histotypes of ovarian carcinomas. Diagnostic typing criteria have evolved over time, and past cohorts may be misclassified by current standards. Our objective was to reclassify the recently assembled Canadian Ovarian Experimental Unified Resource and the Alberta Ovarian Tumor Type cohorts using immunohistochemical (IHC) biomarkers and to develop an IHC algorithm for ovarian carcinoma histotyping. A total of 1626 ovarian carcinoma samples from the Canadian Ovarian Experimental Unified Resource and the Alberta Ovarian Tumor Type were subjected to a reclassification by comparing the original with the predicted histotype. Histotype prediction was derived from a nominal logistic regression modeling using a previously reclassified cohort (N=784) with the binary input of 8 IHC markers. Cases with discordant original or predicted histotypes were subjected to arbitration. After reclassification, 1762 cases from all cohorts were subjected to prediction models (&khgr;2 Automatic Interaction Detection, recursive partitioning, and nominal logistic regression) with a variable IHC marker input. The histologic type was confirmed in 1521/1626 (93.5%) cases of the Canadian Ovarian Experimental Unified Resource and the Alberta Ovarian Tumor Type cohorts. The highest misclassification occurred in the endometrioid type, where most of the changes involved reclassification from endometrioid to high-grade serous carcinoma, which was additionally supported by mutational data and outcome. Using the reclassified histotype as the endpoint, a 4-marker prediction model correctly classified 88%, a 6-marker 91%, and an 8-marker 93% of the 1762 cases. This study provides statistically validated, inexpensive IHC algorithms, which have versatile applications in research, clinical practice, and clinical trials.

Morphologic Reproducibility, Genotyping, and Immunohistochemical Profiling Do Not Support a Category of Seromucinous Carcinoma of the Ovary

The 2014 World Health Organization Classification of Tumors of Female Reproductive Organs endorsed the new category of seromucinous carcinoma, a neoplasm that exhibits morphologic and immunophenotypic overlap with other histotypes of ovarian carcinoma. The goal of this study was to determine whether seromucinous carcinoma was a distinct histotype by assessing its diagnostic reproducibility and comparing its molecular composition to the 5 major histotypes of ovarian carcinoma. Thirty-two tumors diagnosed as seromucinous carcinomas from 2 centers were studied. Eighteen cases were randomly selected for a review set comprising a total of 50 ovarian carcinomas of various histotypes. Morphologic histotype was independently assessed by 4 pathologists. For the 32 seromucinous carcinomas, a histotype-specific immunophenotype was assigned using a diagnostic immunohistochemical panel. Histotype-specific genotype was assigned using a combination of immunohistochemistry and targeted next-generation sequencing for somatic mutations, including genes recurrently mutated in ovarian carcinomas. There was low to modest agreement between pathologists with the reference diagnosis of seromucinous carcinoma, ranging from 39% to 56% for the 4 observers. The immunophenotype was not unique but overlapped predominantly with endometrioid and to a lesser extent with mucinous and low-grade serous carcinoma. Genomic and immunohistochemical alterations were detected in a number of target genes, including KRAS (70%), PIK3CA (37%), PTEN (19%), and ARID1A (16%); no CTNNB1 mutations were identified. Nine cases (30%) harbored concurrent KRAS/PIK3CA mutations. An endometrioid genotype was assigned to 19 cases, a low-grade serous genotype to 9, and a mucinous genotype to 1 and 3 cases were uninformative. Integrating morphology, immunophenotype, and genotyping resulted in reclassifying the seromucinous carcinomas to endometrioid 23/32 (72%), low-grade serous 8/32 (25%), and mucinous 1/32 (3%). The morphologic diagnosis of seromucinous carcinomas is not very reliable and it does not exhibit a distinct immunophenotype or genotype. The molecular features overlap mostly with endometrioid and low-grade serous carcinomas. Our data suggest the category of seromucinous carcinoma be discontinued as ancillary molecular tests can assign cases to one of the major histotypes.

Immunohistochemical Profiling of Endometrial Serous Carcinoma.

Endometrial serous carcinoma (ESC) is an aggressive neoplasm mainly seen in older women. The objective of this study was to refine immunohistochemical (IHC) panels for the differential diagnoses against endometrial endometrioid grade 3 (EC3), endometrial clear cell, and ovarian high-grade serous carcinoma as well as exploring the prognostic role of selected IHC markers. Fifty-two ESC from a single institution were assessed for 20 IHC markers, including ARID1A, CCNE1, CDKN2A, ERBB2, ESR1, HNF1B, FBXW7, IGF2BP3, MLH1, MSH2, MSH6, NAPSA, PAX8, PGR, PMS2, PTEN, TFF3, TP53, VIM, and WT1. ERBB2 chromogenic in situ hybridization was evaluated on tissue microarrays. Statistical analysis was performed. All ESC showed aberrant TP53, normal mismatch repair protein, and retained ARID1A and PTEN expression. ESR1 expression was present in 80% of ESC. A combination of TP53, PTEN, and CDKN2A had a sensitivity of 93.6% [95% confidence interval (CI), 84%–98%] and specificity of 87.8% (95% CI, 75%–95%) for ESC versus EC3. A combination of NAPSA and ESR1 had a sensitivity of 97.9% (95% CI, 89%–99%) and specificity of 72.2% (95% CI, 46%–90%) for ESC versus clear cell carcinoma. Absence of WT1 alone had a sensitivity of 66.0% (95% CI, 51%–79%) and specificity of 98.0% (95% CI, 94%–99%) for ESC versus ovarian high-grade serous carcinoma. Among all 52 ESCs, ERBB2 amplification was present in 23%, FBXW7 expression was absent in 10%, and CCNE1 was overexpressed in 59%, however, none were associated with prognosis. Our data support the value of IHC marker panels for histotyping of high-grade endometrial carcinomas.

Tissue-based Immunohistochemical Biomarker Accuracy in the Diagnosis of Malignant Glandular Lesions of the Uterine Cervix: A Systematic Review of the Literature and Meta-Analysis

Immunohistochemistry is widely used to support a pathology diagnosis of cervical adenocarcinoma despite the absence of a systematic review and meta-analysis of the published data. This systematic review and meta-analysis was performed to investigate the sensitivity and specificity of immunohistochemistry biomarkers in the tissue-based diagnosis of cervical adenocarcinoma histotypes compared with normal endocervix and benign glandular lesions. The systematic review and meta-analysis used a PICOT framework and QUADAS-2 to evaluate the quality of included studies. The literature search spanned 40 years and ended June 30, 2015. Abstracts of identified records were independently screened by 2 of the authors who then conducted a full-text review of selected articles. Sensitivity and specificity of immunohistochemistry expression in malignant glandular lesions of the cervix classified per WHO 2003 compared with 5 benign comparators (normal/benign endocervix, and benign endocervical, endometrioid, gastric, and mesonephric lesions) were calculated. Of 902 abstracts screened, 154 articles were selected for full review. Twenty-five articles with results for 36 biomarkers were included. The only biomarker with enough studies for a meta-analysis was p16 and the definition of positive p16 staining among them was variable. Nevertheless, any positive p16 expression was sensitive, ranging from 0.94 to 0.98 with narrow confidence intervals (CIs), for adenocarcinoma in situ (AIS) and mucinous adenocarcinomas in comparison with normal/benign endocervix and benign endocervical and endometrioid lesions. Specificity for AIS and mucinous adenocarcinomas was also high with narrow CIs compared with benign endocervical lesions. The specificity was high for AIS, 0.99 (0.24, 1.0), and mucinous adenocarcinoma, 0.95 (0.52, 1.0), compared with normal/benign endocervix but with wider CIs, and low with very wide CIs compared with benign endometrioid lesions: 0.31 (0.00, 0.99) and 0.34 (0.00, 0.99), respectively. Results from single studies showed that p16, p16/Ki67 dual stain, ProExC, CEA, ESA, HIK1083, Claudin 18, and ER loss in perilesional stromal cells were useful with high (≥0.75) sensitivity and specificity estimates in ≥1 malignant versus benign comparisons. None of the biomarkers had highly useful sensitivity and specificity estimates for AIS, mucinous adenocarcinomas, or minimal deviation adenocarcinoma/gastric adenocarcinoma compared with benign gastric or mesonephric lesions or for mesonephric carcinoma compared with normal/benign endocervix, benign endocervical, endometrial, or mesonephric lesions. Any expression of p16 supports a diagnosis of AIS and mucinous adenocarcinomas in comparison with normal/benign endocervix and benign endocervical lesions. The majority of studies did not separate mosaic/focal p16 staining from diffuse staining as a distinct pattern of p16 overexpression and this may have contributed to the poor performance of p16 in distinguishing AIS and mucinous adenocarcinomas from benign endometrioid lesions. Single studies support further investigation of 8 additional biomarkers that have highly useful sensitivity and specificity estimates for ≥1 malignant glandular lesions compared with ≥1 of the 5 benign comparators.

Squamous intraepithelial lesions in cervical tissue samples of limited adequacy and insufficient for grading as low or high grade: outcome, clinico-pathological correlates, and predictive role of p16INK4a and Ki67 biomarker staining.

Objective Cervical tissue samples of limited adequacy but with pathological features of squamous intraepithelial lesions (SIL) may not be gradable and result in a diagnosis of ungraded SIL (SILQ). SILQ outcome, clinico-pathological correlates, and the predictive role of biomarker staining are unknown. Materials and Methods Among 17,551 colposcopy attendees, 478 (2.7%) had SILQ. Glass slides of 472 were reviewed. Positive [high SIL (HSIL), adenocarcinoma in situ (AIS), or carcinoma] and negative [negative for intraepithelial lesion or malignancy (NILM) or low SIL (LSIL)] outcomes were based on the worst pathology in 24 months of follow-up. p16INK4a and Ki67 immunohistochemistry of 80 random SILQ and 149 controls (44 NILM, 15 LSIL, 75 HSIL, and 15 AIS) was scored as unsatisfactory, positive, or negative. Biomarker and outcome status were correlated, and sensitivity, specificity positive predictive value (PPV), and negative predictive value (NPV) were calculated. Results Of the total cases, 332 (1.9%) were reviewed as SILQ, and follow-up for 329 was positive in 134 (41%). Atypical glandular cells, AIS, atypical squamous cells (cannot exclude HSIL), HSIL referral Pap test (70% vs 47%, p < .001), and HSIL colposcopic impression (33% vs 19%, p < .001) were more frequent among positive compared with negative outcomes. Best SILQ sensitivity (89%) and NPV (77%) occurred with combined biomarkers, and best specificity (52%) and PPV (58%) occurred with Ki67. All 4 performance metrics among the controls were high. Conclusions The 2% frequency and 41% positive outcome highlight the clinical importance of SILQ. The referral Pap test and colposcopic impression could prioritize follow-up colposcopy for some SILQ, and negative staining with both biomarkers could eliminate further colposcopy in others.