Use of Diffusion-Weighted Imaging and 18F-Fluorodeoxyglucose Positron Emission Tomography Combined With Computed Tomography in the Response Assessment for (Chemo)radiotherapy in Head and Neck Squamous Cell Carcinoma.

AIMS: Our purpose was to assess the diagnostic accuracy and prognostic value of diffusion-weighted imaging (DWI) and 18F-fluorodeoxyglucose positron emission tomography combined with computed tomography (18F-FDG-PET/CT) carried out 3-6 months after (chemo)radiotherapy in head and neck squamous cell carcinoma. MATERIALS AND METHODS: For this retrospective cohort study we included 82 patients with advanced-stage head and neck squamous cell carcinoma treated between 2012 and 2015. Primary tumours and lymph nodes were assessed separately. DWI was analysed qualitatively and quantitatively. 18F-FDG-PET/CT was evaluated using the Hopkins criteria. Dichotomous qualitative analysis was carried out for both modalities. Cox regression analysis was used for univariate analysis of recurrence-free survival (RFS). Significant univariate parameters were included in multivariate analysis. RESULTS: In 12 patients, locoregional recurrence occurred. With all imaging strategies, either single-modality or multi-modality, a high negative predictive value (NPV) was achieved (94.3-100%). In response evaluation of the primary site, the preferred strategy is 18F-FDG-PET/CT only, which resulted in a sensitivity of 85.7%, specificity of 86.5%, positive predictive value (PPV) of 37.5% and NPV of 98.5%. For response evaluation of the neck, the best results were obtained with a sequential approach only including the second modality in positive reads of the first modality. It did not matter which modality was assessed first. This strategy for lymph node assessment resulted in a sensitivity, specificity, PPV and NPV of 83.3%, 95.6%, 62.5%, and 98.5%, respectively. After correction for received treatment and human papillomavirus status, primary tumour (P = 0.009) or lymph node (P < 0.001) Hopkins score ≥4 on 18F-FDG-PET/CT remained significant predictors of RFS. CONCLUSION: For response evaluation of the primary tumour 18F-FDG-PET/CT only is the preferred strategy, whereas for the neck a sequential approach including both DWI and 18F-FDG-PET/CT resulted in the best diagnostic accuracy for follow-up after (chemo)radiotherapy. Qualitative analysis of 18F-FDG-PET/CT is a stronger predictor of RFS than DWI analysis.

Genetic Diversity and Gene Flow of Four South African Venturia inaequalis (Apple Scab) Populations.

Venturia inaequalis isolates were collected during the 2012/13 and 2013/14 seasons from the four principal apple growing regions of South Africa, Elgin (n = 114), Koue Bokkeveld (n = 126), Lower Langkloof (n = 92), and Upper Langkloof (n = 103). Sequence analysis of the ribosomal internal transcribed spacer (ITS) gene regions and genotyping with six (2012/13) and seven (2013/14) microsatellite (SSR) markers was conducted. A subset of 12 isolates from the individual ITS haplotype groups were sequenced for the translation elongation factor-1 alpha (TEF1) and the large subunit of the RNA polymerases II (RPB1) gene regions. Four haplotypes were found for ITS, whereas all isolates were identical for the TEF1 and RPB1 gene regions. The SSR markers revealed considerable variation with an average gene diversity (H) of 0.675. Multivariate analysis (discriminant analysis of principal components [DAPC]) revealed that the two Langkloof populations clustered together with the Koue Bokkeveld population. The population from the warmer winter region, Elgin, clustered separately from the rest of the populations (ΦPT = 0.076 to 0.116; P ≤ 0.05). Estimates of gene flow showed the highest migration rate from the Koue Bokkeveld, toward the Lower Langkloof (M = 151.1), and the least migration to and from the Elgin region (average M = 42.75). Occasionally, identical genotypes (clones) were detected across seasons in the Koue Bokkeveld and Elgin area, which might contribute to overwintering conidia. From this study, it is evident that South Africa most likely has V. inaequalis subpopulations linked to diverse climatic conditions of the coastal Elgin region compared with the mountainous inland regions of the Koue Bokkeveld and the Langkloof.

HER2 positivity in gastric and esophageal adenocarcinoma: clinicopathological analysis and comparison.

PURPOSE: Primary tumor classification of gastric or esophageal cancer has changed significantly with recent alterations of the tumor-node-metastasis (TNM) staging system. Considering these alterations, human epidermal growth factor receptor 2 (HER2) positivity rates were determined and compared in gastric and esophageal adenocarcinoma. Additionally, HER2 positivity in relation to other clinicopathological characteristics was evaluated. METHODS: A total of 321 patients with histologically confirmed invasive gastric or esophageal adenocarcinoma were examined for HER2 by immunohistochemy (IHC) and chromogenic in situ hybridization (CISH). IHC 3+ or IHC 2+/CISH-positive tumors were considered HER2 positive. Clinicopathological characteristics were retrospectively retrieved from the patient records. RESULTS: HER2 positivity was found in 50 of 321 patients (15.6 %). In univariate and multivariate logistic models, HER2 positivity rates were significantly higher in esophageal primary tumors (esophageal 25.0 % vs. gastric 7.4 %) and in intestinal histological tumor type (intestinal 22.6 % vs. diffuse/mixed 5.7 %). No significant differences in HER2 positivity were found between males and females, age below and above 65 years, biopsies and surgical specimens or advanced and early-stage disease. Using the 7th TNM edition, many tumors (30.5 % of all included tumors and 64.5 % of all esophageal primary tumors) previously classified as gastric cancer are now classified as esophageal cancer. CONCLUSIONS: HER2 positivity occurs in 15.6 % of invasive gastroesophageal adenocarcinoma in Western patients, of which the majority is esophageal primary tumors and of the intestinal tumor type. With the introduction of the 7th TNM edition, a large number of tumors previously classified as gastric are now classified as esophageal tumors instead, with relatively high HER2 positivity rates in these esophageal primary tumors.

Xenogeneic transplantation of equine testicular cells into seminiferous tubules of immunocompetent rats.

The objectives were to develop a transplantation assay for equine testicular cells using busulfan-treated prepubertal immunocompetent rats as recipients, and to determine if putative equine spermatogonial stem cells (SSCs) could be enriched by flow cytometric cell sorting (based on light scattering properties), thereby improving engraftment efficiency. Four weeks after transplantation of frozen/thawed PKH26-labeled equine testicular cells, 0.029 ± 0.045% (mean ± SD) of viable donor cells transplanted had engrafted. Donor cells were present in seminiferous tubules of all recipient rats forming chains, pairs, mesh structures, or clusters (with two to >30 cells/structure). Cells were localized to the basal compartment by the basement membrane. Although equine cells proliferated within rat seminiferous tubules, no donor-derived spermatogenesis was evident. Furthermore, there was no histologic evidence of acute cellular rejection. No fluorescent cells were present in control testes. When equine testicular cells were sorted based on light scattering properties, the percentage of transplanted donor cells that engrafted was higher after injection of cells from the small, low complexity fraction (II; 0.169 ± 0.099%) than from either the large, high complexity fraction (I; 0.046 ± 0.051%) or unsorted cells (0.009 ± 0.007%; P < 0.05). Seminiferous tubules of busulfan-treated prepubertal immunocompetent rats provided a suitable niche for engraftment and proliferation, but not differentiation, of equine testicular cells. Sorting equine testicular cells based on light scattering properties resulted in a 19-fold improvement in colonization efficiency by cells with high forward scatter and low side scatter, which may represent putative equine SSCs.

Lineage differentiation of canine lymphoma/leukemias and aberrant expression of CD molecules.

Multiparameter flow cytometry analysis and specific cluster differentiation (CD) molecules were used to determine the expression profiles of B- and T-cell antigens on lymph node preparations from 59 dogs with generalized or multisystemic lymphoma. Lymph node samples from 11 healthy dogs were labeled to validate the specificity of antibodies and to formulate guidelines for interpretation of the results obtained from lymphoma samples. In normal lymph nodes, T-lymphocytes expressing CD3, CD4, or CD8 beta represented 59+/-11%, 43+/-8%, or 16+/-5% of the total cells, whereas B-lymphocytes expressing either CD21 or surface IgM (IgM) represented 37+/-9% or 14+/-5%, respectively. Small lymphocytes could be distinguished from large lymphocytes by forward light scatter. Of the patient samples 29 different breeds were represented with Golden and Labrador retriever being the most common. The lymphoma samples segregated into three groups based on CD antigen expression. Thirty cases predominantly expressed one or more combinations of CD79a, IgM, and CD21 representing a B-cell lineage. Three B-cell cases also expressed the stem cell antigen, CD34. Sixteen cases expressed one or more combinations of CD3, CD4, and CD8 consistent with a T-cell lineage and CD3+CD4+CD8--phenotype was the most common. Thirteen cases showed a mixed expression profile for T- and B-cell antigens and in three cases CD14 was highly expressed. Clinical response was poorest for T-cell lymphomas. Leukemic states occurred in all three phenotypes; but mixed cell cases had the greatest proportion. Dual immunofluorescence staining confirmed co-expression of T-cell (CD3) and B-cell antigens (CD79a or CD21) on neoplastic lymphocytes of six mixed cell cases. In one mixed cell case, dual immunostaining identified lymphocyte populations that stained mutually exclusive for CD79a and CD3. Six mixed cell lymphomas tested by PCR showed clonality for rearranged antigen receptor. Four cases that were CD79a+CD3+ had TCRgamma chain gene rearrangements, whereas two cases that were CD3+CD8+CD21+ had Ig heavy chain rearrangement. One case expressing multiple CD molecules (CD3+CD8+CD21+CD14+) was PCR negative for both Ig and TCRgamma gene rearrangement and could not be classified into a B- or T-cell lineage. We show for the first time co-expression of B- and T-cell markers on lymphoma cells that had specific T- or B-cell gene rearrangements. These findings suggest that aberrant CD molecule expression is not an uncommon finding in canine lymphomas and is a useful diagnostic marker for malignancy.