Trace element content in drinking water of nasopharyngeal carcinoma patients

Exposure to cadmium and head and neck cancers: a meta-analysis of observational studies

Cadmium (Cd) is a widespread environmental pollutant. A number of observational studies have reported that Cd might be a cause of nasopharyngeal (NPC), pharyngeal (PC), or laryngeal cancers (LC). In this study evidence about the relation of Cd and NPC, PC, and LC has been summarized. A literature review was conducted until 20 June 2020 in PubMed, Ovid, Scopus, Web of Science and Google scholar databases to investigate the epidemiologic evidence for the relation between cadmium exposure and cancers of the nasopharynx, pharynx, and larynx. Ten articles were selected after careful screening of retrieved studies. All of these studies obtained a Newcastle-Ottawa Scale (NOS) quality score from 6 to 8. Due to high heterogeneity, in all analyses, random effect was used. The pooled results showed that cadmium levels in NPC (standard mean difference (SMD=0.55; 95% CI=0.20, 0.89; p=0.002) and PC (SMD=9.79; 95% CI=0.62, 18.96; p=0.036) patients/tissues were significantly higher than their controls. But cadmium levels were not significantly different between LC cases/tissues and their controls. (SMD=-0.05; 95% CI=-0.99, 0.89; p=0.921). Exposure to cadmium is likely to cause nasopharyngeal and pharyngeal cancer.

Association of soil arsenic and nickel exposure with cancer mortality rates, a town-scale ecological study in Suzhou, China

Heavy metals and arsenic are well-known carcinogens. However, few studies have examined whether soil heavy metals and arsenic concentrations associate with cancer in the general population. In this ecological study, we aimed to evaluate the association of heavy metals and arsenic in soil with cancer mortality rates during 2005-2010 in Suzhou, China, after controlling for education and smoking prevalence. In 2005, a total of 1683 soil samples with a sampling density of one sample every 4 km(2) were analyzed. Generalized linear model with a quasi-Poisson regression was applied to evaluate the association between town-scale cancer mortality rates and soil heavy metal concentrations. Results showed that soil arsenic exposure had a significant relationship with colon, gastric, kidney, lung, and nasopharyngeal cancer mortality rates and soil nickel exposure was significantly associated with liver and lung cancer. The associations of soil arsenic and nickel exposure with colon, gastric, kidney, and liver cancer in male were higher than those in female. The observed associations of soil arsenic and nickel with cancer mortality rates were less sensitive to alternative exposure metrics. Our findings would contribute to the understanding of the carcinogenic effect of soil arsenic and nickel exposure in general population.

Effect of ethanol extract of Selaginella doederleinii Hieron on the proliferation of nasopharyngeal carcinoma CNE-1 and C666-1 cells

This paper mainly studied the effect of ethanol extract of Selaginella doederleinii Hieron on the proliferation of two kinds of nasopharyngeal carcinoma cell lines, CNE-1 and C666-1, and their mechanisms of action. Extract was obtained by heat reflux extraction with ethanol, and the effect of extract on the extracellular matrix adhesion of the cells, on their proliferation process, as well as on their colony-forming ability were tested using MTT assay. The results showed that the yield of dry extract was 36.4%. 2.5 g/ml extract in the high concentration group exhibited inhibitory activity that was directly proportional to the concentration on CNE-1 cells, while not exhibiting obvious proportional trend in respect with C666-1 cells. However, the inhibition rates against two types of cells can both reach between 30% ~ 50%. Under the effect of ethanol extract of Selaginella doederleinii Hieron, proliferative capacities of C666-1 and CNE-1 cells were affected to some extent.

Non-viral environmental risk factors for nasopharyngeal carcinoma: a systematic review

This review aims to systematically summarize the epidemiological studies on nasopharyngeal carcinoma (NPC) conducted over the past half century, covering descriptive epidemiological studies and reports on non-viral risk factors. Multiple lines of epidemiologic evidence for established risk factors are systematically presented in comprehensive tables. The potential interactions among environmental factors and genetic components, and also the impacts of parallel sequencing technology on the aetiology of NPC are discussed. Finally, we propose a modified model for the pathogenesis of nasopharyngeal carcinoma based on the current knowledge.

The prediction of nasopharyngeal carcinoma mortality based on soil element levels in China

The relationship between the mortality of nasopharyngeal carcinoma (NPC) and soil trace elements of 29 regions of China was investigated. A total of 29 elements (i.e., Mn, Na, K, Mg, Ca, Sr, Ba, Hg, Pb, Se, In, Yb, Lu, Th, U, Sn, Ti, Zr, Hf, Bi, Ta, Te, Br, I, As, Cr, Cu, Fe, and Zn) were considered. A hybrid strategy called genetic algorithm-partial least squares was used to screen out important elements. As a result, only six elements, i.e., Mn, Ti, Mg, K, Na, and I, were picked out, based on which, a PLS model containing two latent variables exhibited the best performance. According to whether the mortality is larger than 2/100,000 (2 × 10(-5)), all the 29 regions were divided into the low-mortality group with 23 regions and the high-mortality group with six regions. Based on the optimal PLS model, all high-mortality regions were successfully classified while only two low-mortality regions were misclassified, i.e., an accuracy of 93%, implying that the selected six elements are effective and successful for predicting the NPC mortality of a region.

The enigmatic epidemiology of nasopharyngeal carcinoma

Nasopharyngeal carcinoma (NPC) has a unique and complex etiology that is not completely understood. Although NPC is rare in most populations, it is a leading form of cancer in a few well-defined populations, including natives of southern China, Southeast Asia, the Arctic, and the Middle East/North Africa. The distinctive racial/ethnic and geographic distribution of NPC worldwide suggests that both environmental factors and genetic traits contribute to its development. This review aims to summarize the current knowledge regarding the epidemiology of NPC and to propose new avenues of research that could help illuminate the causes and ultimately the prevention of this remarkable disease. Well-established risk factors for NPC include elevated antibody titers against the Epstein-Barr virus, consumption of salt-preserved fish, a family history of NPC, and certain human leukocyte antigen class I genotypes. Consumption of other preserved foods, tobacco smoking, and a history of chronic respiratory tract conditions may be associated with elevated NPC risk, whereas consumption of fresh fruits and vegetables and other human leukocyte antigen genotypes may be associated with decreased risk. Evidence for a causal role of various inhalants, herbal medicines, and occupational exposures is inconsistent. Other than dietary modification, no concrete preventive measures for NPC exist. Given the unresolved gaps in understanding of NPC, there is a clear need for large-scale, population-based molecular epidemiologic studies to elucidate how environmental, viral, and genetic factors interact in both the development and the prevention of this disease.

Trace element levels in drinking water and the incidence of colorectal cancer

We determined the levels of 15 elements in drinking water from 34 water treatment plants in Aomori Prefecture and studied how element levels relate to colorectal cancer incidence by district. Colorectal cancer incidence was calculated from the data of Aomori Colorectal Cancer Registry. Multiple regression analysis was performed by using age-adjusted incidences of rectal cancer and colon cancer by gender as object variables and each element level as an explanatory variable. The standardized partial regression coefficient was significant in gold (p < 0.01), magnesium (p < 0.01), selenium (p < 0.01) and tin (p < 0.05) for age-adjusted rectal cancer incidence in men as objective variable; in gold (p < 0.05), calcium (p < 0.01) and phosphorus (p < 0.01) with age-adjusted colon cancer incidence in men as the objective variable; and in sodium (p < 0.05), phosphorus (p < 0.05), tin (p < 0.05) and strontium (p < 0.01) with age-adjusted colon cancer incidence in women as the objective variable. These results confirm the need to further study trace elements in drinking water and food, and relationship to colorectal carcinogenesis.

Survey of trace elements in household and bottled drinking water samples collected in Riyadh, Saudi Arabia

Total dissolved beryllium (Be), cadmium (Cd), chromium (Cr), copper (Cu), iron (Fe), magnesium (Mg), manganese (Mn), mercury (Hg), nickel (Ni), selenium (Se), strontium (Sr), vanadium (V) and zinc (Zn) were measured in the drinking water of 101 households and 21 samples of retail bottled waters purchased in Riyadh, Saudi Arabia to ascertain the water quality for human consumption. The Inductively Coupled Plasma Spectrometer (ICP) was used for analysis. First-draw Fe, Mn, Ni and Zn concentrations decreased significantly after 10 min of flushing in the morning. Cd, Fe, Hg, Ni and Zn in some cases exceeded the guideline limits recommended by the EEC and WHO.

Trace elements in drinking water coolers collected from primary schools, Riyadh, Saudi Arabia

A simple method for the spectrochemical analysis of water samples by inductively coupled plasma spectrometry is described. Samples from drinking water coolers in 32 schools in Riyadh were collected at a specific time during a typical school day and analyzed for aluminum (Al), beryllium (Be), cadmium (Cd), cobalt (Co), chromium (Cr), copper (Cu), iron (Fe), manganese (Mn), molybdenum (Mo), nickel (Ni), silicon (Si), strontium (Sr), vanadium (V), and zinc (Zn) to ascertain the water quality. The analysis of drinking water showed high concentrations of metals and in some cases exceeded the guideline limits recommended by EEC and WHO.