SUMMARY Medullary thyroid carcinoma (MTC) is a neuroendocrine cancer that originates from calcitonin-secreting parafollicular cells, or C cells. We found that Cdk5 and its cofactors, p35 and p25, are highly expressed in human MTC and that Cdk5 activity promotes MTC proliferation. A conditional MTC mouse model was generated and corroborated the role of aberrant Cdk5 activation in MTC. C cell-specific overexpression of p25 caused rapid C cell hyperplasia leading to lethal MTC, which was arrested by repressing p25 overexpression. A comparative phosphoproteomic screen between proliferating and arrested MTC identified the retinoblastoma protein (Rb) as a crucial Cdk5 downstream target. Prevention of Rb phosphorylation at Ser807/811 attenuated MTC proliferation. These findings implicate Cdk5 signaling via Rb as critical to MTC tumorigenesis and progression.

BACKGROUND: Papillary thyroid cancer (PTC) persistence or recurrence and the need for long-term surveillance can cause significant inconvenience and morbidity in patients. Currently, recurrence risk stratification is accomplished by using clinicopathologic factors, and serum thyroglobulin is the only commercially available marker for persistent or recurrent disease. The objective of this study was to determine microRNA (miRNA) expression in PTC and determine whether 1 or more miRNAs could be measured in plasma as a biomarker for recurrence. METHODS: Patients with recurrent PTC (Rc-PTC) and those without recurrence (NR-PTC) were retrospectively recruited for a comparison of their tumor miRNA profiles. Patients with either newly diagnosed PTC or multinodular goiter who were undergoing total thyroidectomy were prospectively recruited for an analysis of preoperative and postoperative circulating miRNA levels. Healthy volunteers were recruited as the control group. RESULTS: MicroRNA-222 and miR-146b were over-expressed 10.8-fold and 8.9-fold, respectively, in Rc-PTC tumors compared with NR-PTC tumors (P 5.014 and P 5.038, respectively). In plasma from preoperative PTC patients, levels of miR-222 and miR-146b were higher compared with the levels in plasma from healthy volunteers (P <.01 for both). Reductions of 2.7-fold and 5.1-fold were observed in the plasma levels of miR-222 and miR-146b, respectively, after total thyroidectomy (P 5.03 for both). CONCLUSIONS: This study demonstrated that tumor levels of miR-222 and miR-146b are associated with PTC recurrence and that miR-222 and miR-146b levels in the circulation correspond to the presence of PTC. The potential of these miRNAs as tumor biomarkers to improve patient stratification according to the risk of recurrence and as circulating biomarkers for PTC surveillance warrants further study. Cancer 2013;119:4358-65.

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A curated Web-based user-friendly sequence typing tool based on antimicrobial resistance determinants in Neisseria gonorrhoeae was developed and is publicly accessible (https://ngstar.canada.ca). The N. gonorrhoeae Sequence Typing for Antimicrobial Resistance (NG-STAR) molecular typing scheme uses the DNA sequences of 7 genes (penA, mtrR, porB, ponA, gyrA, parC, and 23S rRNA) associated with resistance to ␤-lactam antimicrobials, macrolides, or fluoroquinolones. NG-STAR uses the entire penA sequence, combining the historical nomenclature for penA types I to XXXVIII with novel nucleotide sequence designations; the full mtrR sequence and a portion of its promoter region; portions of ponA, porB, gyrA, and parC; and 23S rRNA sequences. NG-STAR grouped 768 isolates into 139 sequence types (STs) (n ϭ 660) consisting of 29 clonal complexes (CCs) having a maximum of a single-locus variation, and 76 NG-STAR STs (n ϭ 109) were identified as unrelated singletons. NG-STAR had a high Simpson's diversity index value of 96.5% (95% confidence interval [CI] ϭ 0.959 to 0.969). The most common STs were NG-STAR ST-90 (n ϭ 100; 13.0%), ST-42 and ST-91 (n ϭ 45; 5.9%), ST-64 (n ϭ 44; 5.72%), and ST-139 (n ϭ 42; 5.5%). Decreased susceptibility to azithromycin was associated with NG-STAR ST-58, ST-61, ST-64, ST-79, ST-91, and ST-139 (n ϭ 156; 92.3%); decreased susceptibility to cephalosporins was associated with NG-STAR ST-90, ST-91, and ST-97 (n ϭ 162; 94.2%); and ciprofloxacin resistance was associated with NG-STAR ST-26, 98.0%). All isolates of NG-STAR ST-42, ST-43, ST-63, ST-81, and ST-160 (n ϭ 106) were susceptible to all four antimicrobials. The standardization of nomenclature associated with antimicrobial resistance determinants through an internationally available database will facilitate the monitoring of the global dissemination of antimicrobial-resistant N. gonorrhoeae strains.

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The gene CDC73 (previously known as HRPT2) encodes the protein parafibromin. Biallelic mutation of CDC73 is strongly associated with malignancy in parathyroid tumors. Heterozygous germline mutations cause hyperparathyroidism jaw tumor syndrome,which is associated with a high life-time risk of parathyroid carcinoma. Therefore loss of parafibromin expression by immunohistochemistry may triage genetic testing for hyperparathyroidism jaw tumor syndrome and be associated with malignant behavior in atypical parathyroid tumors. We share our experience that parafibromin-negative parathyroid tumors show distinctive morphology. We searched our institutional database for parathyroid tumors demonstrating complete loss of nuclear expression of parafibromin with internal positive controls. Forty-three parafibromin-negative tumors from 40 (5.1%) of 789 patients undergoing immunohistochemistry were identified. Thirty-three (77%) were external consultation cases; the estimated incidence in unselected tumors was 0.19%. Sixteen (37.2%) fulfilled World Health Organization 2017 criteria for parathyroid carcinoma and 63% had serum calcium greater than 3mmol/L. One of 27 (3.7%) noninvasive but parafibromin-negative tumors subsequently metastasized. Parafibromin-negative patients were younger (mean, 36 vs. 63 y; P<0.001) and had larger tumors (mean, 3.04 vs. 0.62 g; P<0.001). Not all patients had full testing, but 26 patients had pathogenic CDC73 mutation/deletions confirmed in tumor (n=23) and/or germline (n=16). Parafibromin-negative tumors demonstrated distinctive morphology including extensive sheet-like rather than acinar growth, eosinophilic cytoplasm, nuclear enlargement with distinctive coarse chromatin, perinuclear cytoplasmic clearing, a prominent arborizing vasculature, and, frequently, a thick capsule. Microcystic change was found in 21 (48.8%). In conclusion, there are previously unrecognized morphologic clues to parafibromin loss/CDC73 mutation in parathyroid tumors which, given the association with malignancy and syndromic disease, are important to recognize.This is an open-access article distributed under the terms of the Creative Commons Attribution-Non Commercial-No Derivatives License 4.0 (CCBY-NC-ND), where it is permissible to download and share the work provided it is properly cited. The work cannot be changed in any way or used commercially without permission from the journal. http://creativecommons.org/licenses/by-nc-nd/4.0/.

Identification of BRAF V600E in thyroid neoplasia may be useful because it is specific for malignancy, connotes a worse prognosis, and is the target of novel therapies currently under investigation. Sanger sequencing is the 'gold standard' for mutation detection but is subject to sampling error and requires resources beyond many diagnostic pathology laboratories. In this study, we compared immunohistochemistry (IHC) using a BRAF V600E mutation-specific MAB to Sanger sequencing on DNA from formalin-fixed paraffin-embedded tissue, in a well-characterized cohort of 101 papillary thyroid carcinoma (PTC) patients. For all cases, an IHC result was available; however, five cases failed Sanger sequencing. Of the 96 cases with molecular data, 68 (71%) were BRAF V600E positive by IHC and 59 (61%) were BRAF V600E positive by sequencing. Eleven cases were discordant. One case was negative by IHC and initially positive by sequencing. Repeat sequencing of that sample and sequencing of a macrodissected sample were negative for BRAF V600E. Of ten cases positive by IHC but negative by sequencing on whole sections, repeat sequencing on macrodissected tissue confirmed the IHC result in seven cases (suggesting that these were false negatives of sequencing on whole sections). In three cases, repeat sequencing on recut tissue remained negative (including using massive parallel sequencing), but these cases demonstrated relatively low neoplastic cellularity. We conclude that IHC for BRAF V600E is more sensitive and specific than Sanger sequencing in the routine diagnostic setting and may represent the new gold standard for detection of BRAF V600E mutation in PTC.

Introduction: Bloodstream infections due to Candida species are becoming a major cause of morbidity and mortality in hospitalized patients. The spectrum of candidemia has changed with the emergence of non-albicans Candida species, especially among critically ill patients. Methodology: In a retrospective study (July 2009 to December 2009) on candidemia, various Candida species isolated from blood cultures were characterized and studied along with the determination of their antifungal susceptibility to amphotericin B, itraconazole, and fluconazole by Etest. Probable risk factors for patients in the intensive care unit (ICU) presenting with candidemia were also analyzed. Results: During the study period, a total of 4651 samples were received, out of which 468 samples (10.06%) were positive for growth of organisms: 441 (94.20%) aerobic bacterial pathogens and 27 (5.79%) Candida species. The most common Candida spp. isolate was C. tropicalis (40.8%) followed by C. albicans (29.6%), C. glabrata (18.5%) and others (11.1%). Out of the 27 Candida strains, 24 (88.9%) were isolated from patients treated in the ICU. Among these, association of previous use of broad-spectrum antibiotics in 22 patients (91.6%) and central line catheter insertion in 20 patients (83.3%) were found to be statistically significant as compared to non-candidemia patients (p <0.05). Antifungal susceptibility testing of the isolates revealed a lower level of drug resistance to amphotericin B (18.5% of the isolates) versus 77.8% resistance to fluconazole. Conclusion: Rapid changes in the rate of infection, potential risk factors, and emergence of non-albicans Candida demand continued surveillance of this serious bloodstream fungal infection.