Differential Expression of VEGF-Axxx Isoforms Is Critical for Development of Pulmonary Fibrosis.

RATIONALE: Fibrosis after lung injury is related to poor outcome, and idiopathic pulmonary fibrosis (IPF) can be regarded as an exemplar. Vascular endothelial growth factor (VEGF)-A has been implicated in this context, but there are conflicting reports as to whether it is a contributory or protective factor. Differential splicing of the VEGF-A gene produces multiple functional isoforms including VEGF-A165a and VEGF-A165b, a member of the inhibitory family. To date there is no clear information on the role of VEGF-A in IPF. OBJECTIVES: To establish VEGF-A isoform expression and functional effects in IPF. METHODS: We used tissue sections, plasma, and lung fibroblasts from patients with IPF and control subjects. In a bleomycin-induced lung fibrosis model we used wild-type MMTV mice and a triple transgenic mouse SPC-rtTA+/-TetoCre+/-LoxP-VEGF-A+/+ to conditionally induce VEGF-A isoform deletion specifically in the alveolar type II (ATII) cells of adult mice. MEASUREMENTS AND MAIN RESULTS: IPF and normal lung fibroblasts differentially expressed and responded to VEGF-A165a and VEGF-A165b in terms of proliferation and matrix expression. Increased VEGF-A165b was detected in plasma of progressing patients with IPF. In a mouse model of pulmonary fibrosis, ATII-specific deficiency of VEGF-A or constitutive overexpression of VEGF-A165b inhibited the development of pulmonary fibrosis, as did treatment with intraperitoneal delivery of VEGF-A165b to wild-type mice. CONCLUSIONS: These results indicate that changes in the bioavailability of VEGF-A sourced from ATII cells, namely the ratio of VEGF-Axxxa to VEGF-Axxxb, are critical in development of pulmonary fibrosis and may be a paradigm for the regulation of tissue repair.

Foamy Macrophage Deposition in Lymph Nodes Mimicking Lung Cancer Recurrence Diagnosed via Endobronchial Ultrasound-Guided Transbronchial Needle Aspiration.

The radiological finding of mediastinal lymph node enlargement following surgery for lung cancer often signifies locoregional recurrence. The use of oxidised cellulose haemostatic agents (OCHAs) during staging mediastinoscopy is common. We report a case of 18-fluorodeoxyglucose-avid subcarinal lymphadenopathy in a patient in whom OCHAs had been used at mediastinoscopy 5 months earlier. Histopathological examination of suspected nodal recurrence is facilitated by endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA). The technique is particularly useful after previous mediastinoscopy, when repeat surgical exploration can be challenging. EBUS-TBNA samples showed extensive foamy macrophage deposition, with no evidence of malignancy. The association between the use of OCHAs and subsequent intranodal foamy macrophage deposition is new. Clinicians should consider this possibility in the differential diagnosis of mediastinal lymphadenopathy after surgical exploration, where OCHAs have been left in situ; it remains important to resample the lymph nodes before assuming disease recurrence to prevent unnecessary treatment.

Circulating levels of anti-angiogenic VEGF-A isoform (VEGF-Axxxb) in colorectal cancer patients predicts tumour VEGF-A ratios.

PURPOSE: Bevacizumab as an adjunct to chemotherapy improves survival for some patients with metastatic colorectal cancer. Immunohistochemical staining of samples from the registration ECOG E3200 trial of bevacizumab with FOLFOX demonstrated that only patients with carcinomas expressing low levels of VEGF-A165b, an anti-angiogenic splice variant of the Vascular Endothelial Growth Factor family of proteins, benefited from bevacizumab treatment. To identify a more useful biomarker of response we tested the hypothesis that circulating VEGF-A165b levels correlate with immunohistochemical staining. EXPERIMENTAL DESIGN: 17 patients with biopsy proven colorectal adenocarcinoma had pre-operative blood samples drawn. They underwent resection and had post-resection blood drawn. The plasma was analysed for levels of VEGF-Axxxb using enzyme-linked immunosorbent assay (ELISA) and the tumour blocks stained for VEGF-Axxxb and pan-VEGF-A. The normalised ratio of VEGF-Axxxb expression to that of panVEGF-A expression scored by IHC was calculated and correlated with plasma VEGF-A165b levels. RESULTS: Plasma levels of VEGF-Axxxb significantly correlated with the VEGF-Axxxb:panVEGF-A ratio (r=0.594, P<0.02) in colorectal cancers. Median plasma VEGF-Axxxb levels were 151 pg/ml. The mean (1.5±0.17) and median, IQR (1.8, 1-2) IHC scores of the patients with greater than median plasma VEGF-Axxxb were significantly greater than those with less than median plasma VEGF-Axxxb levels (mean ± SEM=0.85±10.12, median, IQR=1, 0.54-1). CONCLUSION: These results suggest that plasma VEGF-Axxxb levels could be an effective biomarker of response to Bevacizumab. These results indicate that a prospective trial is warranted to explore the use of plasma VEGF-Axxxb levels to stratify patients for colorectal cancer treatment by bevacizumab.

Multidisciplinary perspective on the management of appendiceal adenocarcinoma: case review of 10 patients from a university hospital and current considerations.

BACKGROUND: Adenocarcinoma of the vermiform appendix is rare. It constitutes less than 0.5% of all gastrointestinal malignancies. Pathologically, appendiceal neoplasms are categorized into various subtypes depending on cell lineage. PATIENTS AND METHODS: We considered a case series of appendiceal invasive adenocarcinomas from 2004 to 2013 managed in a teaching hospital. We discuss our management dilemmas, given the lack of randomized controlled trial data that exist. A detailed look at the histopathology, case series, and literature is presented. RESULTS: Ideal standards ought to be constructed for the management of this rare pathology, with a particular focus on exploring the indications and potential benefits, as well as difficulties, of ileocolic lymphadenectomy. CONCLUSION: Appendiceal adenocarcinoma ought to be managed in the same way as a cecal adenocarcinoma.

Impact of needle gauge on characterization of endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) histology samples.

BACKGROUND AND OBJECTIVE: Endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) is a minimally invasive mediastinal node sampling technique used for lung cancer staging and diagnosis of mediastinal lesions. The four published studies assessing sampling with 21-G or 22-G needles conflict. The study objective is to evaluate the diagnostic utility of 21-G versus 22-G EBUS-TBNA needles, and the ability to subcharacterize both benign and malignant lesions using histopathological assessment only. METHODS: A retrospective analysis was performed from 303 patients referred for EBUS-TBNA between January 2011 and July 2013. Sampling needle gauge was selected at the discretion of the operator. Samples were assessed by histopathologists blinded to the needle gauge without rapid on-site evaluation for cytology. Contingency table analysis was performed to compare diagnostic utility and ability to subcharacterize malignant and benign lesions. RESULTS: No difference in diagnostic ability was seen for malignancy (96.6% vs. 95.3% accuracy, 21-G vs. 22-G). Subgroup analysis of benign 21-G tissue samples revealed superior characterization compared with 22-G samples (63/76, 83%, vs. 31/52, 60%, P < 0.01). Characterization of non-small cell lung cancer (NSCLC) was also significantly better with samples obtained with 21-G needles versus 22-G needles (57/65, 88% vs. 34/52, 65%, P < 0.01). CONCLUSIONS: This large UK single-centre study suggests 21-G EBUS-TBNA needles are superior to 22-G in characterizing benign lesions (especially sarcoidosis) and NSCLC when using histopathological assessment. Making a positive benign diagnosis may avoid the need to perform mediastinoscopy. Obtaining sufficient histological material to subcharacterize NSCLC and particularly lung adenocarcinoma allows appropriate testing for genetic mutations facilitating targeted oncological therapy.

The connective tissue changes of Crohn's disease.

Although the inflammatory pathology of Crohn's disease is manifestly its most important attribute, the connective tissue changes are important in the genesis of the more chronic features of the disease, and yet these have received little attention from clinicians, pathologists, and scientists. Fat-wrapping appears to be pathognomonic of Crohn's disease, and is an important marker of disease for surgeons. There is evidence of a complex interplay between the effector inflammatory cells of Crohn's disease and adipocytes, hyperplasia of which results in fat-wrapping. Pathologically, this is exhibited in the close relationship between the transmural inflammation that is so characteristic of Crohn's disease and fat-wrapping. Fibrosis and muscularization are also important components of the chronic changes of intestinal Crohn's disease. Neuronal and vascular changes make up the remaining connective tissue changes: these constitute a distinctive feature, and are even specific for Crohn's disease. For pathologists, the combination of these connective changes will allow a diagnosis of chronic 'burnt-out' Crohn's disease, even in the absence of its highly characteristic inflammatory features. The connective tissue changes of Crohn's disease form an important part of its long-term pathology. They deserve more attention from clinicians, diagnostic pathologists and researchers alike.

Specificity of DOG1 (K9 clone) and protein kinase C theta (clone 27) as immunohistochemical markers of gastrointestinal stromal tumour.

AIMS: DOG1 and protein kinase C (PKC) theta are both sensitive immunohistochemical markers of gastrointestinal stromal tumour (GIST). However, there are conflicting data regarding the specificity of the most commonly used PKC theta antibody (clone 27), and there are no existing data regarding the specificity of the only known commercially available DOG1 antibody (K9 clone) at the time of writing. This study's aim was to characterize the immunoreactivity patterns of both monoclonal antibodies amongst a wide range of neoplasm types including, in particular, histological mimics of GIST. METHODS AND RESULTS: Immunohistochemistry for DOG1 and PKC theta was performed on whole tissue sections from 23 different neoplasm types (total of 125 cases). Ten of these neoplasm types showed CD117 immunopositivity. Only three (Ewing's sarcoma, glomus tumour and synovial sarcoma) of the 23 neoplasm types showed DOG1 immunopositivity, and such positivity was often focal and weak in intensity. In contrast, all but four (ganglioneuromas, leiomyomas, desmoplastic small round cell tumours and PEComa/angiomyolipomas) of the 23 neoplasm types showed PKC theta immunopositivity. CONCLUSIONS: Compared with CD117, DOG1 (using the K9 antibody) is a more specific marker, whereas PKC theta (using the clone 27 antibody) is a considerably less specific immunohistochemical marker for GIST.