High Erk-1 activation and Gadd45a expression as prognostic markers in high risk pediatric haemolymphoproliferative diseases

Global expression profiling of CD10 + /CD19 + pre-B lymphoblasts from Hispanic B-ALL patients correlates with comparative TARGET database analysis

Mexico City has one of the highest incidences of acute lymphoblastic leukemia (ALL) globally, with patients showing low survival, and high relapse rates. To gain more insight into the molecular features of B-ALL in Mexican children, we isolated CD10 + /CD19 + precursor B lymphoblasts from four bone marrow and nine peripheral blood samples of B-ALL patients using a fluorescence-activated cell sorting protocol. The global gene expression profile (BM vs PB) revealed 136 differentially expressed genes; 62 were upregulated (45.6%) and 74 were downregulated (54.4%). Pearson's correlation coefficient was calculated to determine the similarity between pre-B lymphoblast populations. We selected 26 highly significant genes and validated 21 by RT-qPCR (CNN3, STON2, CALN1, RUNX2, GADD45A, CDC45, CDC20, PLK1, AIDA, HCK, LY86, GPR65, PIK3CG, LILRB2, IL7R, TCL1A, DOCK1, HIST1H3G, PTPN14, CD72, and NT5E). The gene set enrichment analysis of the total expression matrix and the ingenuity pathway analysis of the 136 differentially expressed genes showed that the cell cycle was altered in the bone marrow with four overexpressed genes (PLK1, CDC20, CDC45, and GADD45A) and a low expression of IL7R and PIK3CG, which are involved in B cell differentiation. A comparative bioinformatics analysis of 15 bone marrow and 10 peripheral blood samples from Hispanic B-ALL patients collected by the TARGET program, corroborated the genes observed, except for PIK3CG. We conclude the Mexican and the Hispanic B-ALL patients studied present common driver alterations and histotype-specific mutations that could facilitate risk stratification and diagnostic accuracy and serve as potential therapeutic targets.

Involvement of the central nervous system in acute lymphoblastic leukemia: opinions on molecular mechanisms and clinical implications based on recent data

Acute lymphoblastic leukemia (ALL) is the most common childhood cancer. One of the major clinical challenges is adequate diagnosis and treatment of central nervous system (CNS) involvement in this disease. Intriguingly, there is little solid evidence on the mechanisms sustaining CNS disease in ALL. Here, we present and discuss recent data on this topic, which are mainly derived from preclinical model systems. We thereby highlight sites and routes of leukemic CNS infiltration, cellular features promoting infiltration and survival of leukemic cells in a presumably hostile niche, and dormancy as a potential mechanism of survival and relapse in CNS leukemia. We also focus on the impact of ALL cytogenetic subtypes on features associated with a particular CNS tropism. Finally, we speculate on new perspectives in the treatment of ALL in the CNS, including ideas on the impact of novel immunotherapies.

The functional interplay between the t(9;22)-associated fusion proteins BCR/ABL and ABL/BCR in Philadelphia chromosome-positive acute lymphatic leukemia

The hallmark of Philadelphia chromosome positive (Ph⁺) leukemia is the BCR/ABL kinase, which is successfully targeted by selective ATP competitors. However, inhibition of BCR/ABL alone is unable to eradicate Ph⁺ leukemia. The t(9;22) is a reciprocal translocation which encodes not only for the der22 (Philadelphia chromosome) related BCR/ABL, but also for der9 related ABL/BCR fusion proteins, which can be detected in 65% of patients with chronic myeloid leukemia (CML) and 100% of patients with Ph⁺ acute lymphatic leukemia (ALL). ABL/BCRs are oncogenes able to influence the lineage commitment of hematopoietic progenitors. Aim of this study was to further disclose the role of p96^ABL/BCR for the pathogenesis of Ph⁺ ALL. The co-expression of p96^ABL/BCR enhanced the kinase activity and as a consequence, the transformation potential of p185^BCR/ABL. Targeting p96^ABL/BCR by RNAi inhibited growth of Ph⁺ ALL cell lines and Ph⁺ ALL patient-derived long-term cultures (PD-LTCs). Our in vitro and in vivo stem cell studies further revealed a functional hierarchy of p96^ABL/BCR and p185^BCR/ABL in hematopoietic stem cells. Co-expression of p96^ABL/BCR abolished the capacity of p185^BCR/ABL to induce a CML-like disease and led to the induction of ALL. Taken together our here presented data reveal an important role of p96^ABL/BCR for the pathogenesis of Ph⁺ ALL.

The t(9;22) is a reciprocal translocation, which causes chronic myeloid leukemia (CML) and a subset of high risk acute lymphatic leukemia (ALL). The derivative chromosome 22 is the so called Philadelphia chromosome (Ph) which encodes the BCR/ABL kinase. Targeting BCR/ABL by selective ATP competitors, such as imatinib or nilotinib, is a well validated therapeutic concept, but unable to definitively eradicate the disease. Little is known about the role of the fusion protein encoded by the reciprocal derivative chromosome 9, the ABL/BCR. In models of Ph⁺ ALL we show that the functional interplay between ABL/BCR and BCR/ABL not only increases the transformation potential of BCR/ABL but is also indispensable for the growth and survival of Ph⁺ ALL leukemic cells. The presence of ABL/BCR changed the phenotype of the leukemia most likely due to its capacity to influence the stem cell population as shown by our in vivo data. Taken together our here presented data reveal an important role of p96^ABL/BCR for the pathogenesis of Ph⁺ ALL.

Mer tyrosine kinase promotes the survival of t(1;19)-positive acute lymphoblastic leukemia (ALL) in the central nervous system (CNS)

Mer mediates quiescence and chemotherapy resistance in a CNS coculture model and causes CNS infiltration in immunodeficient mice. Mer expression correlates with CNS positivity upon initial diagnosis in t(1;19)-positive pediatric ALL patients.

Extracellular signal-regulated kinase (ERK) expression and activation in mobile tongue squamous cell carcinoma: associations with clinicopathological parameters and patients survival

Extracellular signal-regulated kinase (ERK) has been considered as a critical regulator of diverse cellular processes such as proliferation, survival and motility, being implicated in the malignant transformation in several tissue types. The present study aimed to evaluate the clinical significance of total ERK1 (t-ERK1) and phosphorylated ERK1/2 (p-ERK1/2) protein expression in mobile tongue squamous cell carcinoma (SCC). t-ERK1 and p-ERK1/2 protein expression in tumour cells and infiltrating the tumour microenvironment lymphoid cells was assessed immunohistochemically on 47 mobile tongue SCC tissue samples and was analyzed in relation with clinicopathological characteristics, overall and disease-free patients' survival. Enhanced nuclear t-ERK1 and p-ERK1/2 expression in tumour cells was associated with the absence of perineural invasion (p = 0.043) and shorter overall patients' survival (log-rank test, p = 0.028), respectively. Enhanced t-ERK1 expression in infiltrating lymphoid cells was significantly associated with female gender, absence of vascular and perineural invasion, lymph node metastases and early depth of invasion (p = 0.008, p = 0.019, p = 0.011, p = 0.036 and p = 0.001, respectively), as well as with longer disease-free survival times (log-rank test, p = 0.038). Enhanced p-ERK1/2 expression in infiltrating lymphoid cells was significantly associated with the presence of vascular invasion and lymph node metastases (p = 0.019 and p = 0.004, respectively) and shorter overall patients' survival (log-rank test, p = 0.013). In multivariate analysis, p-ERK1/2 expression in tumour cells and infiltrating lymphoid cells was identified as independent prognostic factors of overall survival (Cox regression analysis, p = 0.045 and p = 0.032, respectively). The present study supported evidence that ERK signalling pathway may exert a potential role in the pathophysiological aspects of the mobile tongue SCC, presenting also potential utility as a biomarker for patients' survival and reinforcing the development of novel anti-cancer therapies targeting ERK signalling cascade in this type of human malignancy.