Association between Serum Level of Multiple Trace Elements and Esophageal Squamous Cell Carcinoma Risk: A Case-Control Study in China

Lead (Pb) in biological samples in association with cancer risk and mortality: A systematic literature review

BACKGROUND AND AIM

Lead (Pb) is a toxic heavy metal and pervasive environmental contaminant, and a class 2 A carcinogen according to the IARC classification, yet its link with cancer at several body sites remains uncertain. Here, we aimed at summarizing the scientific evidence regarding its association with cancer risk and mortality, focusing on studies that carried out Pb measurements in biological samples.

METHODS

We reviewed articles published in PubMed and EMBASE until January 2nd, 2024, that quantified the epidemiological association between Pb measured in blood, urine, nails, and other biological media, and cancer risk and mortality (overall and by cancer site/type).

RESULTS

We included 46 articles (out of 8022 screened) published in 1995-2023 and reporting on investigations conducted in fifteen countries. In terms of design, 20 were prospective, 24 were retrospective case-control studies, and 2 were cross-sectional. Pb levels were determined in blood in the majority of studies (n=28). The most consistent evidence was for the association of Pb with cancer of the gastrointestinal tract, particularly the oesophagus, stomach (RR ranging from 0.80 to 2.66), colon-rectum, and pancreas; and of the bladder and urinary tract (RR from 1.10 to 2.89). For other specific malignancies, the data were conflicting or too limited to draw reliable conclusions. Finally, increased Pb concentration in blood and urine was consistently associated with higher overall cancer incidence and mortality.

CONCLUSIONS

Lead is a widespread and highly persistent environmental pollutant associated with cancer at multiple body sites. Comprehensive primary prevention interventions aiming at reducing opportunities for Pb exposure need to be continuously promoted and implemented.

Silver Nanoparticles Cause Neural and Vascular Disruption by Affecting Key Neuroactive Ligand-Receptor Interaction and VEGF Signaling Pathways

Introduction

Silver nanoparticles (AgNP) are widely used as coating materials. However, the potential risks of AgNP to human health, especially for neural and vascular systems, are still poorly understood.

Methods

The vascular and neurotoxicity of various concentrations of AgNP in zebrafish were examined using fluorescence microscopy. In addition, Illumina high-throughput global transcriptome analysis was performed to explore the transcriptome profiles of zebrafish embryos after exposure to AgNP. Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses were conducted to elucidate the top 3000 differentially expressed genes (DEGs) between AgNP-exposed and control groups.

Results

We systematically investigated the neural and vascular developmental toxicities of AgNP exposure in zebrafish. The results demonstrated that AgNP exposure could cause neurodevelopmental anomalies, including a small-eye phenotype, neuronal morphology defects, and inhibition of athletic abilities. In addition, we found that AgNP exposure induces angiogenesis malformation in zebrafish embryos. Further RNA-seq revealed that DEGs were mainly enriched in the neuroactive ligand-receptor interaction and vascular endothelial growth factor (Vegf) signaling pathways in AgNP-treated zebrafish embryos. Specifically, the mRNA levels of the neuroactive ligand-receptor interaction pathway and Vegf signaling pathway-related genes, including si:ch73-55i23.1, nfatc2a, prkcg, si:ch211-132p1.2, lepa, mchr1b, pla2g4aa, rac1b, p2ry6, adrb2, chrnb1, and chrm1b, were significantly regulated in AgNP-treated zebrafish embryos.

Conclusion

Our findings indicate that AgNP exposure transcriptionally induces developmental toxicity in neural and vascular development by disturbing neuroactive ligand-receptor interactions and the Vegf signaling pathway in zebrafish embryos.

Associations of trace element levels in paired serum, whole blood, and tissue: an example of esophageal squamous cell carcinoma

Previous studies have extensively explored impacts of trace elements on human beings and complex relationships with cancers. However, contradictory conclusions may be more challenging to explain due to biological specimen differences. To investigate the distribution of trace elements inside body, we collected serum, whole blood and tissues from 77 patients with esophageal squamous cell carcinoma (ESCC), as well as serum and whole blood from 100 healthy individuals, and determined the concentrations of 13 elements (Al, V, Cr, Mn, Co, Ni, Cu, Zn, As, Se, Sr, Cd, and Pb) with inductively coupled plasma-mass spectrometry (ICP-MS). Al, Ni, Cu, Sr, and Cd variations between patients and controls were found to be inconsistent in serum and blood. Concentrations of Cu, As, Se, and Sr in serum were positively correlated with that in whole blood in both case and control group (r_s >0.450, P <0.01). Elements in serum had a higher accuracy (87.0%) than whole blood (74.0%) in classifying ESCC patients and healthy individuals with discriminant analysis. As, Cd, and Pb concentrations in cancerous tissues were positively correlated with those in normal epithelium (r_s =0.397, 0.571, and 0.542, respectively), while Mn, Cu, and Se accumulated in malignant tissues, with V, Cr, Co, Ni, Sr, and Cd partitioning in normal epithelium (all P <0.05). Thus, certain elements in blood, such as Cu, As, Se, and Sr, were useful in assessing element exposure burdens and accumulation tendency of some elements (Mn, Cu and Se, etc.) was uncovered in tumors. Our investigation demonstrated the variations in trace element distribution for frequently used specimens and further evidence of etiological mechanism is necessary.