Although cancer is characterized by an intratumoral genetic heterogeneity, a totally deranged pH control is a common feature of most cancer histotypes. Major determinants of aberrant pH gradient in cancer are proton exchangers and transporters, including V-ATPase, Na+/H+ exchanger (NHE), monocarboxylate transporters (MCTs) and carbonic anhydrases (CAs). Thanks to the activity of these proton transporters and exchangers, cancer becomes isolated and/or protected not only from the body reaction against the growing tumor, but also from the vast majority of drugs that when protonated into the acidic tumor microenvironment do not enter into cancer cells. Proton transporters and exchangers represent a key feature tumor cells use to survive in the very hostile microenvironmental conditions that they create and maintain. Detoxifying mechanisms may thus represent both a key survival option and a selection outcome for cells that behave as unicellular microorganisms rather than belonging to an organ, compartment or body. It is, in fact, typical of malignant tumors that, after a clinically measurable yet transient initial response to a therapy, resistant tumor clones emerge and proliferate, thus bursting a more malignant behavior and rapid tumor progression. This review critically presents the background of a novel and efficient approach that aims to fight cancer through blocking or inhibiting well characterized proton exchangers and transporters active in human cancer cells. This article is part of a Special Issue entitled: Membrane channels and transporters in cancers.

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Objectives: The COVID-19 (SARS-CoV-2) pandemic is an ongoing public health challenge, also for the dentistry community. The main objective of this paper was to determine the economic and health-care impact of COVID-19 on dentists in the Autonomous Region of Galicia (Spain). Methods: This was a descriptive observational study in which the data was collected by means of a self-administered survey (from 1 April 2020 to 30 April 2020). Results: A total of 400 dentists from Galicia responded to the survey. Only 12.3% of the participants could obtain personal protective equipment (PPE) including FFP2 masks. Of the male respondents, 33.1% suffered losses >€15,000 compared to 19.4% of female respondents (OR = 3.121, p < 0.001). Economic losses seem to have contributed to the applications for economic help as 29.5% of the respondents who applied for this measure recorded losses in excess of €15,000 (p = 0.03). Patients complained more about the fact that only emergency care was available during the State of Alarm, in dental surgeries that do not work with insurance companies or franchises. Only 4 professionals tested positive, 50% of whom worked exclusively in private practice and the other 50% who practised in both private and public surgeries. Dentists who practise in the public sector saw more urgent patients per week than those practising in private surgeries (p = 0.013). Conclusions: The COVID-19 pandemic has had economic repercussions in dentistry as only urgent treatment was available during the State of Alarm. These repercussions seem to be higher in male participants, as the majority of the participants have revealed higher economic losses than females. The level of assistance has also been affected, reducing the number of treated patients, although this quantity has been different in private and public surgeries. By presenting these findings we look to highlight the role that dentists play in society in treating dental emergencies in our surgeries, and this must be recognised and addressed by the relevant authorities, who must provide PPEs as a priority to this group as well as providing special economic aid in accordance with the losses incurred by the sector.

BackgroundOral leukoplakia is the most common potentially malignant disorder (PMD) of the oral cavity. The objectives of this study are to determine the clinicopathologic features in a group of patients with oral leukoplakia of Northern Spain (Galicia), determining the factors associated to clinical risk and analyzing the malignant transformation of these patients.Material and MethodsWe included 85 patients. We recorded sex and age, habits like alcohol and tobacco, size, clinical appearance, site, number of lesions, and presence or absence of dysplasia. We assess the association between risk factors and transformation and developed a logistic regression analysis. Finally we used the Kaplan-Meier and log-rank test for the survival analysis.Results7 patients (8.2%) had malignant transformation. The mean follow-up of the patients was 4.13 years versus 5.58 years of those who developed carcinoma. Only location and initial dysplasia have a statistically significant relationship with malignant transformation, but when applied the long rank test only the presence of dysplasia remains statistically significant(P<0,026). Oral Cancer Free Survival was 81.9% (0.150) at 11 years for the group without dysplasia.ConclusionsWe found that the presence of dysplasia is the only risk factor that is statistically related to the development of a carcinoma. Key words:Leukoplakia, oral cancer and oral precancer, follow-up, malignant transformation.