Loss of antigenicity with tissue age in breast cancer.

Archived tumor specimens, particularly those collected by large cooperative groups and trials, provide a wealth of material for post hoc clinical investigation. As these tissues are rigorously collected and preserved for many decades, subsequent use of the specimens to answer clinical questions must rely on the assumption that expression and detection of target biomarkers are not degraded with time. To test this assumption, we measured the expression of estrogen receptor (ER), human epidermal growth receptor 2 (HER2), and Ki67 in human breast carcinoma using quantitative immunofluorescence (QIF) in a series of formalin-fixed paraffin-embedded (FFPE) tissues from 1295 individual patients preserved for 7 to 53 years in four cohorts on tissue microarrays. Protein expression was measured using the automated quantitative analysis method for QIF. Change in quantitative protein expression over time was estimated in positive cases using both Pearson's correlation and a polynomial regression analysis with a random effects model. The average signal decreased with preservation time for all biomarkers measured. For ER and HER2, there was an average of 10% signal loss after 9.9 years and 8.5 years, respectively, compared with the most recent tissue. Detection of Ki67 expression was lost more rapidly, with 10% signal loss in just 4.5 years. Overall, these results demonstrate the need for adjustment of tissue age when studying FFPE biospecimens. The rate of antigenicity loss is biomarker specific and should be considered as an important variable for studies using archived tissues.

Polysomnographic abnormalities in succinic semialdehyde dehydrogenase (SSADH) deficiency.

OBJECTIVES: Patients with SSADH deficiency, a disorder of chronically elevated endogenous GABA and GHB, were studied for sleep symptoms and polysomnography. We hypothesized that patients would have excessive daytime somnolence and decreased REM sleep. DESIGN: Polysomnography and MSLT were performed on patients enrolled for comprehensive clinical studies of SSADH deficiency. SETTING: Sleep studies were obtained in the sleep laboratories at CNMC and NIH. PATIENTS: Sleep recordings were obtained in 10 patients with confirmed SSADH deficiency. INTERVENTIONS: Thirteen overnight polysomnograms were obtained in 10 patients (7 male, 3 female, ages 11-27 y). Eleven MSLT studies were completed in 8 patients. MEASUREMENTS AND RESULTS: Polysomnograms showed prolongation of REM stage latency (mean 272 +/- 89 min) and decreased percent stage REM (mean 8.9%, range 0.3% to 13.8%). Decreased mean sleep latency was present in 6 of 11 MSLTs. CONCLUSIONS: SSADH deficiency is associated with prolonged latency to stage REM and decreased percent stage REM. This disorder represents a model of chronic GABA and GHB accumulation associated with suppression of REM sleep.

Triple-negative breast cancers with amplification of JAK2 at the 9p24 locus demonstrate JAK2-specific dependence.

Amplifications at 9p24 have been identified in breast cancer and other malignancies, but the genes within this locus causally associated with oncogenicity or tumor progression remain unclear. Targeted next-generation sequencing of postchemotherapy triple-negative breast cancers (TNBCs) identified a group of 9p24-amplified tumors, which contained focal amplification of the Janus kinase 2 (JAK2) gene. These patients had markedly inferior recurrence-free and overall survival compared to patients with TNBC without JAK2 amplification. Detection of JAK2/9p24 amplifications was more common in chemotherapy-treated TNBCs than in untreated TNBCs or basal-like cancers, or in other breast cancer subtypes. Similar rates of JAK2 amplification were confirmed in patient-derived TNBC xenografts. In patients for whom longitudinal specimens were available, JAK2 amplification was selected for during neoadjuvant chemotherapy and eventual metastatic spread, suggesting a role in tumorigenicity and chemoresistance, phenotypes often attributed to a cancer stem cell-like cell population. In TNBC cell lines with JAK2 copy gains or amplification, specific inhibition of JAK2 signaling reduced mammosphere formation and cooperated with chemotherapy in reducing tumor growth in vivo. In these cells, inhibition of JAK1-signal transducer and activator of transcription 3 (STAT3) signaling had little effect or, in some cases, counteracted JAK2-specific inhibition. Collectively, these results suggest that JAK2-specific inhibitors are more efficacious than dual JAK1/2 inhibitors against JAK2-amplified TNBCs. Furthermore, JAK2 amplification is a potential biomarker for JAK2 dependence, which, in turn, can be used to select patients for clinical trials with JAK2 inhibitors.

Bolstering the case for lobectomy in stages I, II, and IIIA small-cell lung cancer using the National Cancer Data Base.

INTRODUCTION: Current therapy for small-cell lung cancer (SCLC) relies on chemoradiation therapy, and the role of primary surgical resection in these patients remains controversial. A minority of SCLC patients present without metastatic disease and are candidates for surgery. This study investigates the role of surgical resection in select patients with SCLC, using a national cohort of approximately 2500 resected patients. METHODS: A retrospective study of SCLC patients in the National Cancer Data Base (NCDB) was performed where patients were grouped for comparison by stage and treatment regimen. Survival was estimated by Kaplan-Meier methods and multivariate comparisons using Cox regression. RESULTS: Of 28,621 cases of potentially resectable SCLC, 2476 patients (9%) underwent surgery of the primary site with curative intent. Five-year overall survival for patients after resection was 51%, 25%, and 18% for clinical stages I, II, and IIIA, respectively. Addition of surgery to chemotherapy was associated with decreased likelihood of death (hazard ratio: 0.57, 95% confidence interval: 0.47-0.68), independent of age, stage, and comorbidity score. Lobectomy was associated with a 5-year overall survival of 40% compared with 21% and 22% for sublobar resection and pneumonectomy, respectively. Hazard ratio for death after sublobar resections compared with lobectomy was 1.38 (95% confidence interval: 1.12-1.71). CONCLUSIONS: Patients with stages I, II, and III SCLC, who underwent surgical resection as part of initial treatment with chemotherapy had respectable OS. These data may warrant prospective studies of including surgery in the multimodality treatment of SCLC in specific circumstances.

Assessment of genetics knowledge and skills in medical students: insight for a clinical neurogenetics curriculum.

The pace of discovery in biochemistry and genetics and its effect on clinical medicine places new curricular challenges in medical school education. We sought to evaluate students' understanding of neurogenetics and its clinical applications to design a pilot curriculum into the clinical neurology clerkship. We utilized a needs assessment and a written examination to evaluate the genetics knowledge of 81 third- and fourth-year medical students. The needs assessment surveyed students' self-perceptions of their own understanding of basic and clinically related genetic principles and clinical skills, as well as the most effective educational methods. Medical students reported more competence with basic science learned during the preclinical years than clinical concepts, and they demonstrated relatively low knowledge levels in clinical neurogenetics concepts on the examination, with an average of 29% correct on questions pertaining to genetic counseling compared with 82% correct with regard to inheritance patterns. Common, cross-specialty clinical skills were attained (e.g. internet search, family histories), while at least half of students reported minimal understanding or awareness of key genetics websites (e.g. OMIM) and indications for support group recommendations and genetics referrals. Teaching these more specific genetics skills and concepts needs to be emphasized in the clinical curriculum.

The structure and transcriptional analysis of a global regulator from Neisseria meningitidis.

Neisseria meningitidis, a causative agent of bacterial meningitis, has a relatively small repertoire of transcription factors, including NMB0573 (annotated AsnC), a member of the Lrp-AsnC family of regulators that are widely expressed in both Bacteria and Archaea. In the present study we show that NMB0573 binds to l-leucine and l-methionine and have solved the structure of the protein with and without bound amino acids. This has shown, for the first time that amino acid binding does not induce significant conformational changes in the structure of an AsnC/Lrp regulator although it does appear to stabilize the octameric assembly of the protein. Transcriptional profiling of wild-type and NMB0573 knock-out strains of N. meningitidis has shown that NMB0573 is associated with an adaptive response to nutrient poor conditions reflected in a reduction in major surface protein expression. On the basis of its structure and the transcriptional response, we propose that NMB0573 is a global regulator in Neisseria controlling responses to nutrient availability through indicators of general amino acid abundance: leucine and methionine.