Anaplastic lymphoma kinase (ALK) is a receptor tyrosine kinase predominantly expressed in the developing nervous system. Recently, mutated ALK has been identified as a major oncogene associated with familial and sporadic neuroblastomas (NBL). Yet, a direct correlation between endogenous expression level of the ALK protein, oncogenic potential, and clinical outcome has not been established. We investigated ALK genetic mutations, protein expression/ phosphorylation, and functional inhibition both in NBLderived cell lines and in 34 localized and 48 advanced/ metastatic NBL patients. ALK constitutive phosphorylation/ activation was observed in high-ALK expressing cells, harboring either a mutated or a wild-type receptor. No activation was found in cell lines with low expression of wild-type ALK. After 72 hours of treatments, small molecule ALK inhibitor CEP-14083 (60 nmol/L) induced growth arrest and cell death in NBL cells overexpressing wild-type (viability: ALK high 12.8%, ALK low 73%, P = 0.0035; cell death: ALK high 56.4%, ALK low 16.2%, P = 0.0001) or mutated ALK. ALK protein expression was significantly up-regulated in advanced/metastatic compared with localized NBLs (ALK overexpressing patients: stage 1-2, 23.5%; stage 3-4, 77%; P < 0.0001). Interestingly, protein levels did not always correlate with ALK genetic alterations and/or mRNA abundance. Both mutated and wild-type ALK receptor can exert oncogenic activity in NBL cells. However, wild-type ALK receptor requires a critical threshold of expression to achieve oncogenic activation. Overexpression of either mutated or wild-type ALK defines poor prognosis patients. Alternative mechanisms other than direct mutations and/or gene amplification regulate the ALK level of expression in NBL cells. Wild-type ALK is a potential therapeutic target for advanced/metastatic NBLs.
The rapid spread of coronavirus disease 2019 epidemic in Italy, in particular in the Milan focal point, required drastic measures and led to panic in the population. While in our center we did not change our approach to the treatment of our young patients with cancer, we developed a qualitative survey to assess their perception of the risk and level of stress. The survey showed that a relatively large proportion of young patients felt personally at risk of severe complications. We believe that we need to adequately inform our patients, focusing on hygienic measures and personal protection and prompt reporting of any suspicious symptoms.
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