The transcription factor FOXP3 plays a key role in CD4 + CD25 + regulatory T cell function and represents a specific marker for these cells. Despite its strong association with regulatory T cell function, in humans little is known about the frequency of CD4 + CD25 + cells that express FOXP3 protein nor the distribution of these cells in vivo. Here we report the characterization of seven anti-FOXP3 monoclonal antibodies enabling the detection of endogenous human FOXP3 protein by flow cytometry and immunohistochemistry. Flow-cytometric analysis showed that FOXP3 was expressed by the majority of CD4

No abstract

The online version of this article has a Supplementary Appendix. BackgroundPlasmablastic lymphoma has recently come to be considered a distinct entity among mature B cell neoplasms, although the limits with diffuse large B-cell lymphoma (DLBCL) need to be more accurately defined. Design and MethodsHere we show the results of an immunohistochemical study of 35 cases of plasmablastic lymphoma compared with a set of 111 conventional DLBCLs . ResultsOur results demonstrate that the use of a limited combination of immunohistochemical markers (PAX5&CD20, PRDM1/BLIMP1 and XBP1s) enables the identification of a plasmablastic immunophenotype highly characteristic of plasmablastic lymphoma cases and associated with an aggressive clinical behavior. Additionally, the study shows that the acquisition of a partial plasmablastic phenotype (PRDM1/BLIMP1 expression) in DLBCL is associated with shorter survival in R-CHOP-treated patients. ConclusionsThe use of a restricted combination of immunohistochemical markers (PAX5&CD20, PRDM1/BLIMP1 and XBP1s) enables a more accurate definition of terminal differentiation for large B-cell lymphoma.Key words: plasmablastic lymphoma, terminal B-cell differentiation. Citation: Montes-Moreno S, Gonzalez-Medina

LKB1, mutated in Peutz-Jeghers and in sporadic lung tumours, phosphorylates a group of protein kinases named AMP-activated protein kinase (AMPK)-related kinases. Among them is included the AMPK, a sensor of cellular energy status. To investigate the relevance of LKB1 in lung carcinogenesis, we study several lung cancer cells with and without LKB1-inactivating mutations. We report that LKB1-mutant cells are deficient for AMPK activity and refractory to mTOR inhibition upon glucose depletion but not growth-factor deprivation. The requirement for wild-type LKB1 to properly activate AMPK is further demonstrated in genetically modified cancer cells. In addition, LKB1-deficient lung primary tumours had diminished AMPK activity, assessed by complete absence or low level of phosphorylation of its critical substrate, acetyl-CoA carboxylase. We also demonstrate that LKB1 wild-type cells are more resistant to cell death upon glucose withdrawal than their mutant counterparts. Finally, modulation of AMPK activity did not affect PI3K/AKT signalling, an advantage for the potential use of AMPK as a target for cancer therapy in LKB1 wildtype tumours. Thus, sustained abrogation of cell energetic checkpoint control, through alterations at key genes, appear to be an obligatory step in the development of some lung tumours.

No abstract