STAT6 and phosphorylated STAT6 are differentially expressed in lymphomas

BACKGROUND

The STAT6 pathway is implicated in the pathogenesis of various lymphomas; however, its immunohistochemical expression has not been fully investigated. Thus, the aim of this study was to investigate the immunohistochemical expression of the two forms of STAT6, phosphorylated or not, in a series of systemic lymphomas.

MATERIALS AND METHODS

Immunohistochemical expression of two antibodies, STAT6 (clone YE361) and pSTAT6 (clone Y641), which recognise the phosphorylated form of the molecule was studied in 60 lymphomas.

RESULTS

STAT6^YE361 expression was cytoplasmic, with 23.3% of the cases showing high expression. pSTAT6^Y641 expression was mostly nuclear and found in 45% of the cases. pSTAT6^Y641 nuclear expression was associated with the lymphoma type (p < 0.0001), as it was seen mostly in follicular, Hodgkin and angioimmunoblastic T cell lymphomas. STAT6^YE361 cytoplasmic expression was also associated with lymphoma type (p = 0.001), as it was mostly found in diffuse large B cell and marginal B cell lymphomas. No association with PD-L1 expression, other clinicopathological data or prognosis was found.

CONCLUSION

The two STAT6 clones are differentially expressed between lymphoma types.

Brain metastasis PD-L1 and CD8 expression is dependent on primary tumor type and its PD-L1 and CD8 status

Background

Brain metastases (Bmets) are frequent; however, limited data exist on the efficacy of immunotherapy in these lesions. The aims of the study were to analyze the immunohistochemical expressions of programmed death ligand 1 (PD-L1) and CD8 in Bmets and to compare them with their expressions in paired primary tumors, as well as correlate the results with clinicopathological features.

Methods

This is a retrospective study of 233 patients with Bmets and 111 paired primaries. Clinical, histological, and molecular data were recorded and compared with the immunohistochemical results of PD-L1 and CD8 expressions. The statistical analysis included χ² test, Cramer’s V test, factorial analyses of variance, simple regression analysis, and Kaplan-Meier analysis with log-rank product limit estimation.

Results

PD-L1 expression was found in 23.6% of Bmets and in 29.0% of primary tumors with concordant expression between them in 75.5% of cases. Bmets PD-L1 expression was associated with primary tumor PD-L1 expression and the primary tumor type. Significant CD8 peritumoral expression was found in 68.6% of Bmets and in 87.7% of primary tumors. CD8 expression was concordant between primary and metastatic tumors in 73.3% of cases. Bmets CD8 expression was associated with primary tumor CD8 expression and primary tumor type. PD-L1 expression was associated with CD8 expression in both primary and metastatic tumors. The concordance between primary and metastatic tumor PD-L1 expression was independent of all factors studied. The concordance between primary and metastatic CD8 expressions was marginally associated to the time of Bmets development. No prognostic role for PD-L1 and CD8 expression in Bmets was found.

Conclusion

PD-L1 and CD8 Bmets expressions are associated with the primary tumor type and its PD-L1 and CD8 expressions. No factor predicts the discordance for PD-L1 expression, while time to Bmets development is associated with CD8 expression discordance.

Expression of STAT6 and Phosphorylated STAT6 in Primary Central Nervous System Lymphomas

The signal transducer and activator of transcription 6 (STAT6) is implicated in the pathogenesis of some lymphomas including primary central nervous system lymphomas (PCNSLs). The aim of this study was to investigate STAT6 expression and clinicopathologic features in 25 PCNSLs using immunohistochemistry with 2 different anti-STAT6 antibodies. One (YE361) recognizes the C-terminus domain of the STAT6 protein and the other (Y641) recognizes the phosphorylated form of the protein. The phosphorylated STAT6 form was not expressed in any of the cases studied whereas the YE361 STAT6 showed only cytoplasmic expression in 14 (56%) cases. This expression did not correlate with age, prognostic score, multiplicity, invasion of deep structures, response to treatment, disease recurrence, overall survival, or BCL6, BCL2, PD-L1, and CD8 expression. A STAT6 expression score showed a trend for correlating with clinical performance status. It also showed a positive correlation with MYC expression. Thus, the phosphorylated form of STAT6 was not found in the current series, while the YE361 STAT6 showed only cytoplasmic expression and was associated with expression of MYC.

Senescence, immune microenvironment, and vascularization in cardiac myxomas

AIMS

Cardiac myxomas are rare tumors of incompletely elucidated pathogenesis. The aim of this study is to explore the possible presence of a senescence phenotype in cardiac myxomas, associated with an inflammatory and vasculogenic tumor microenvironment.

METHODS AND RESULTS

This is a retrospective study of 29 cardiac myxomas with immunohistochemical detection of various inflammatory, vascular, and senescence markers. We show that all myxomas contain tumor cells in senescence overexpressing p16, and a fraction of senescent endothelial cells. Macrophages are the principal inflammatory cell population, followed by cytotoxic T cells, with fewer plasma cells, mastocytes, and B lymphocytes. These populations are found in different intratumoral localizations. Larger tumor volume is associated with a lower percentage of myxoid matrix, higher cellularity, higher macrophage, and lower number of mast cells as well as higher PD-L1 expression by inflammatory cells. Higher vascular density is associated with higher percentage of B cells, a lower number of macrophages and higher number of mastocytes, and lower PD-L1 expression by inflammatory cells. Tumors with higher vascular density and higher cellularity show higher amounts of p16 senescent endothelial cells.

CONCLUSIONS

Myxoma tumor cells are in senescence and reside inside a tumor microenvironment with a distinct inflammatory profile rich in macrophages and cytotoxic T cells, and a rich vasculature, probably attributed to a senescence-associated secretory phenotype.

Exploring the Wind-Borne Spread of Highly Pathogenic Avian Influenza H5N8 During the 2016-2017 Epizootic in France

In winter 2016-2017, highly pathogenic avian influenza (HPAI) H5N8 virus spread in France, causing an unprecedented epizootic. During the epidemic, southwest France, where most outbreaks were reported, experienced severe weather, with three consecutive storms (Leiv, Kurt, and Marcel) from 3 to 5 February 2017. Although little information is available, one hypothesis is that the spread of HPAI-H5N8 from an infected poultry holding could have been passively facilitated by prevailing wind during the risk period. The aim of this study was therefore to assess the contribution of the wind-borne route to the spatial distribution of HPAI H5N8 outbreaks during the risk period at the beginning of February 2017. The PERLE model, an atmospheric dispersion model (ADM) developed by Météo-France, the French meteorological agency, was used to generate the predicted area at risk of infection from a suspected point source. Model outputs show that the spatial pattern of dust-particle deposition was directed east-southeast in accordance with wind direction. This contrasted with the spatial distribution of HPAI H5N8 outbreaks, which spread westward. These observations suggest that the wind-borne route alone was insufficient to explain the spatial distribution of outbreaks over large distances in southwest France at the beginning of February 2017. Finally, this study illustrates the relevance of close collaboration between governmental authorities, veterinary research institutes, and meteorological agencies involving interdisciplinary research for successful outbreak investigations.

Granular cell tumor a study of 42 cases and systemic review of the literature

BACKGROUND

Granular cell tumor (GCT) remains a diagnostic clinicopathologic problem because the exact frequency of its detailed morphological and clinical characteristics is unknown as most observations are collected from small series or isolated cases. Herein, our aim is to highlight the frequency of all clinicopathological characteristics of this rare tumor based in our series and the available medical (PubMed) literature.

MATERIAL AND METHODS

42 cases were evaluated for: tissue layers involved by the tumor (in skin and mucosae), growth pattern, nuclear pleomorphism, mitotic index, necrosis, spindling, calcification, hyalinization, and pustule-ovoid bodies of Milian, as well as perineural and vascular invasion, and the presence of adjacent epithelium changes, and lymphocytes and eosinophils infiltration., Follow-up was analyzed. The tumors were subclassified into benign, atypical and malignant according to Fanburg-Smith criteria and into benign or GCT of uncertain malignant potential according to Nasser criteria. The same characteristics were analyzed for 1499 cases reviewed according to PRISMA guidelines.

RESULTS

In the current series, the mean age at diagnosis was 45.8 years (range 6-69 years). Most patients were females (60 %) and the involved organs were by descending frequency: skin and subcutaneous tissue, bronchus, esophagus, breast, tongue, larynx, pharynx, gingiva, trachea, right colon, vulva, and hypopharynx. No recurrence or progression was seen, despite 32 cases were incompletely excised, with the exception of one malignant tumor. The growth pattern was either infiltrative (85.71 %) or well limited (7.14 %). Sixteen tumors had vesicular nuclei. Mitotic activity was found in two tumors. Lymphocytic infiltration was found in 14 tumors. Eosinophils were present in 6 cases. One GCT of the right colon showed extensive calcification and hyalinization. Perineural invasion was noted in 6 lesions. No vascular invasion was found. One tumor was clinically malignant and the patient died 2 years after diagnosis. Medical literature review showed similar results in terms of frequency of the reported clinical and morphological features. Among cases with available follow up, almost 20 % showed positive margins and of those 20 % developed local recurrence. According to the Fanburg-Smith criteria, 72 % would be benign, 17 % atypical and 11 % malignant tumors, while according to those of Nasser, 93 % would be benign and 7% of uncertain malignant potential. However, true malignancy, as affirmed by metastasis of GCT is found in almost 2.5 % of the cases.

CONCLUSION

GCT is a usually benign tumor, affecting any anatomic location. Necrosis and mitotic activity seem to be the most effective histologic criteria for detecting aggressive tumors, but the presence of metastasis (2.5 % of the cases) remains the most accepted definitive criterion for diagnosis of malignant GCT.