Incorporating oral, inhalation and dermal bioaccessibility into human health risk characterization following exposure to Chromated Copper Arsenate (CCA)-contaminated soils.

Exposure to potentially toxic metal(loid)s (PTMs) in soil may happen via ingestion, inhalation, and dermal pathway. A more accurate risk characterization should consider PTM bioavailability. Using ten soil samples collected in the Montreal area (Canada) near CCA-treated utility poles, this study aims to characterize non-carcinogenic and carcinogenic human health risks associated with As, Cr, Cu, Pb, and Zn through a multi-pathway exposure approach. This innovative study incorporates, for the first time, the bioaccessible fraction of the metal(loid)s for three exposure routes and two different scenarios. For the residential and industrial scenarios, the oral and dermal pathways yielded a hazard index (HI) much higher than 1 with and without bioaccessibility considerations (range 1.7 - 349 without bioaccessibility and 0.8-134 with bioaccessibility), whereas the inhalation pathway caused a lower hazard (HI < 1). For the dermal pathway, the hazard quotient was higher when bioaccessibility of field-collected samples was considered due to inherent assumptions from the US EPA soil approach to calculate the dermal dose. For carcinogenic risk, As and Pb were the most significant contributors to risk for the oral pathway, followed by the same elements for the dermal pathway. The overall carcinogenic risk was higher than the acceptable risk ( > 10-4) with and without bioaccessibility considerations (range 1.9E-4 - 9.6E-3 without bioaccessibility and 6.8E-5 - 3.8E-3 with bioaccessibility). Bioaccessibility tests provide a more accurate assessment of exposure to PTMs compared to total concentrations in soils.

Age differences in relation to bone thickness and length of the zygomatic process of the maxilla, infrazygomatic crest, and buccal shelf area.

INTRODUCTION: The purpose of this study was to compare the thickness and length of the zygomatic process (ZP) of the maxilla, infrazygomatic crest area, and mandibular buccal shelf by sex and age. METHODS: Cone-beam computed tomography images of 128 subjects were divided into 3 groups: (1) 22 female and 19 male subjects aged 9-13 years, (2) 27 female and 20 male subjects aged 14-23 years, and (3) 20 female and 20 male subjects aged 24-50 years. A previously calibrated operator was used to take all measurements of the zygomatic process vertical bone thickness, zygomatic process horizontal bone length, zygomatic process/cementoenamel length (ZP/CEJL), infrazygomatic crest region bone thickness (IZCBT), infrazygomatic crest region bone length (IZCL), and mandibular buccal shelf bone thickness. Analysis of variance and Kruskal-Wallis tests were used for statistical analyses. Two-way analysis of variance was used for variables with significant differences by sex (P <0.002 as determined by Bonferroni correction for multiple comparisons). RESULTS: Differences by sex were only found for IZCL in the maxillary second premolar and first molar (U5-U6) and the maxillary first molar (U6). Significant differences were observed among age groups for ZP/CEJL, IZCBT in U5-U6 and U6, and IZCL in U6-distal. CONCLUSIONS: The results suggest that ZP/CEJL and IZCL are larger in adults than in younger subjects, whereas IZCBT is smaller in adults than in younger subjects.

Comparison of Synthetic Sweat and Influence of Sebum in the Permeation of Bioaccessible Metal(loid)s from Contaminated Soils through a Synthetic Skin Membrane.

Dermal exposure to metal(loid)s from contaminated soils has received less attention than oral and inhalation exposure. Still, it can be a relevant pathway for some contaminants. Comparison of synthetic sweats (donor solutions), the influence of sebum, and the characterization of diffusion parameters through a synthetic membrane (acting as skin surrogate) in the permeation of metal(loid)s (As, Cr, Cu, Ni, Pb, and, Zn) from polluted soils is missing. The dermal bioaccessibility tests were performed using two sweat compositions [EN 1811, pH 6.5 (sweat A) and NIHS 96-10, pH 4.7 (sweat B)]. Diffusion parameters of soluble metal(loid)s using the Franz cell methodology were calculated using the Strat-M membrane. The influence of synthetic sebum in the permeation of metal(loid)s was also investigated. The metal(loid) bioaccessibility percentage was higher for sweat B (pH 4.7) compared to sweat A (pH 6.5), attributed to lower pH of sweat B. Among the six elements tested, only chromium and copper permeated the membrane. Permeation coefficient (Kp) was higher for chromium in sweat A (0.05-0.11 cm h-1) than sweat B (0.0007-0.0037 cm h-1) likely due to a higher pH and thus more permeable Cr species. The presence of sebum increased lag times for copper permeation. Additional studies regarding speciation of metal(loid)s following extractions in synthetic sweat and comparison of synthetic membrane Strat-M and human skin in the permeation of metal(loid)s are recommended.

Population and breast cancer patients' analysis reveals the diversity of genomic variation of the BRCA genes in the Mexican population.

Interpretation of variants of unknown significance (VUS) in genetic tests is complicated in ethnically diverse populations, given the lack of information regarding the common spectrum of genetic variation in clinically relevant genes. Public availability of data obtained from high-throughput genotyping and/or exome massive parallel sequencing (MPS)-based projects from several thousands of outbred samples might become useful tools to evaluate the pathogenicity of a VUS, based on its frequency in different populations. In the case of the Mexican and other Latino populations, several thousands of samples have been genotyped or sequenced during the last few years as part of different efforts to identify common variants associated to common diseases. In this report, we analyzed Mexican population data from a sample of 3985 outbred individuals, and additional 66 hereditary breast cancer patients were analyzed in order to better define the spectrum of common genomic variation of the BRCA1 and BRCA2 genes. Our analyses identified the most common genetic variants in these clinically relevant genes as well as the presence and frequency of specific pathogenic mutations present in the Mexican population. Analysis of the 3985 population samples by MPS identified three pathogenic mutations in BRCA1, only one population sample showed a BRCA1 exon 16-17 deletion by MLPA. This resulted in a basal prevalence of deleterious mutations of 0.10% (1:996) for BRCA1 and 11 pathogenic mutations in BRCA2, resulting in a basal prevalence of deleterious mutations of 0.276% (1:362) for BRCA2, combined of 0.376% (1:265). Separate analysis of the breast cancer patients identified the presence of pathogenic mutations in 18% (12 pathogenic mutations in 66 patients) of the samples by MPS and 13 additional alterations by MLPA. These results will support a better interpretation of clinical studies focused on the detection of BRCA mutations in Mexican and Latino populations and will help to define the general prevalence of deleterious mutations within these populations.

[Impact on quality of life with breast reconstructive surgery after mastectomy for breast cancer]. / Impacto en la calidad de vida con cirugía reconstructiva posterior al tratamiento de cáncer de mama.

BACKGROUND: Breast cancer treatment leads mutilation and destruction of breast shape, with negative effects on body image and self-esteem. OBJECTIVES: Assessment on quality of life after breast reconstruction surgery, impact on sexuality, the cosmetic outcome experienced by the patient, and compare result with patients who refused breast reconstruction. MATERIAL AND METHODS: Retrospective, observational, descriptive, analytic study. We included breast cancer patients treated between April 15 2010 to April 15, 2011. Application of "The Survey Questionnaire short form Health 36" (SF-36) with valid use on Mexican population was conducted to measure quality of life, which uses 8 concepts: physical functioning, physical role, body pain, general health, vitality, social function, emotional role and mental health, the results are transferred to a scale 0 (worst health) to 100 (best health). RESULTS: 37 patients whit breast reconstruction had the inclusion criteria, mean age was 48.4 years. The score of SF-36 questionnaire in reconstructed patients was 76.8, in control group was 85.19 and mastectomy patients without reconstruction was 72.6. Among the items studied those with the greatest difference was the mental health, emotional role and social function, this means that patients with breast reconstruction are less affected in their social and sexual interaction. CONCLUSIONS: The reconstructed patients have a positive impact on quality of life slightly higher, sexuality is significantly worse in patients without breast reconstruction, it is important to inform and offer breast reconstruction because many do not require these procedures for fear or lack of information.

Metal(loid) speciation in dermal bioaccessibility extracts from contaminated soils and permeation through synthetic skin.

Dermal exposure to metal(loid)s from contaminated soils can contribute to health risk. Metal(loid) speciation will influence their bioaccessibility in sweat and subsequent permeation across the skin. Therefore, the speciation of the bioaccessible fraction of metal(loid)s in two synthetic sweat formulations (sweat A (pH 6.5) and B (pH 4.7)) was assessed using chemical equilibrium modelling (Visual MINTEQ). Permeation through synthetic skin and the influence of sebum in the permeation of As, Cr, Cu, Ni, Pb, and Zn were also investigated using Franz cells. Following dermal bioaccessibility tests for five Chromated Copper Arsenate (CCA)-contaminated soils and one certified soil (SQC001), mean metal(loid) bioaccessibility (%) was higher in sweat B (2.33-18.8) compared to sweat A (0.12-7.53). Arsenic was almost entirely found as As(V) in both sweats. In sweat A, comparable concentrations of Cr(III) and Cr(VI) were found whereas in sweat B, Cr was primarily present as Cr(III). Copper was primarily found as Cu2+. Bioaccessible Cr extracted from nearly all soils permeated through the Strat-M membrane when it was coated with sebum. The Cr permeation coefficient (Kp) ranged between 0.004 and 0.13 cm/h and the Kp for Cu was higher (0.024-0.52 cm/h). As, Ni, Pb, and Zn did not permeate the synthetic skin.

Predictive factors of invasion in ductal carcinoma in situ diagnosed by core-needle biopsy.

OBJECTIVE: To identify clinical, radiological, and histopathological characteristics that could be predictive factors of microinvasive/invasive breast carcinoma in patients with diagnosis of ductal carcinoma in situ (DCIS) by core-needle biopsy. MATERIAL AND METHODS: This is a retrospective study conducted from 2006-2017, which included women ≥18 years of age with initial DCIS, and who were treated with surgery. Final diagnosis was divided in DCIS and microinvasive/invasive carcinoma. RESULTS: 334 patients were included: 193 (57.8%) with DCIS and 141 (42.2%) with microinvasive/invasive carcinoma (microinvasive 5.1%, invasive 37.1%). Lymph node metastasis occurred in 16.3%. Differences between DCIS and microinvasive/invasive groups included the presence of palpable nodule (36.7% vs. 63.2%), radiological nodule (29% vs. 51%), bigger radiological-tumor size (1.2 cm vs. 1.7 cm), and larger microcalcification extension (2.5 cm vs. 3.1 cm), all of these variables p ≤0.05. Hormonal receptors and HER2 expression were similar. After logistic regression analysis, predictive factor of invasion was the presence of palpable nodule (OR = 4.072, 95%CI = 2.520-6.582, p <0.001) and radiological multicentric disease (OR = 1.677, 95%CI = 1.036-2.716, p = 0.035). CONCLUSIONS: In patients with DCIS, palpable nodule, and radiological multicentric disease, upgrade to microinvasive/invasive is high, and sentinel lymph node is recommended.

OBJETIVO: Identificar características clínicas, radiológicas e histopatológicas como factores predictivos de carcinoma mamario microinvasor/invasor en pacientes con Carcinoma Ductal In Situ (CDIS) diagnosticado mediante aguja de corte. MATERIAL Y MÉTODOS: Estudio retrospectivo de 2006­2017, en mujeres ≥18 años con CDIS diagnosticado con aguja de corte y tratadas con cirugía. Los diagnósticos finales fueron CDIS y carcinoma microinvasor/invasor. RESULTADOS: Se incluyeron 334 pacientes, 193 (57.8%) con CDIS y 141 (42.2%) con carcinoma microinvasor/invasor (microinvasor 5.1%, invasor 37.1%). Hubo 16.3% casos con afección ganglionar. Las diferencias entre el grupo de CDIS y carcinoma microinvasor/invasor fue la presencia de tumor palpable (36.7% vs. 63.2%), nódulo visto por imagen (29% vs. 51%), tumores más grandes (1.2 cm vs. 1.7 cm), y mayor extensión de microcalcificaciones (2.5 cm vs. 3.1 cm), estas variables con p ≤0.05. Los receptores hormonales y HER2 fueron similares. En el análisis de regresión logística, los factores predictivos de invasión fueron tumor palpable (OR = 4.072, IC95% = 2.520­6.582, p <0.001) y multicentricidad radiológica (OR = 1.677, IC95% = 1.036­2.716, p = 0.035). CONCLUSIONES: En CDIS, tumor palpable y enfermedad multicéntrica radiológica, el escalamiento a carcinoma microinvasor/invasor es alto y es recomendable realizar ganglio centinela.

Comprehensive omic characterization of breast cancer in Mexican-Hispanic women.

Breast cancer is a heterogeneous pathology, but the genomic basis of its variability remains poorly understood in populations other than Caucasians. Here, through DNA and RNA portraits we explored the molecular features of breast cancers in a set of Hispanic-Mexican (HM) women and compared them to public multi-ancestry datasets. HM patients present an earlier onset of the disease, particularly in aggressive clinical subtypes, compared to non-Hispanic women. The age-related COSMIC signature 1 was more frequent in HM women than in those from other ancestries. We found the AKT1E17K hotspot mutation in 8% of the HM women and identify the AKT1/PIK3CA axis as a potentially druggable target. Also, HM luminal breast tumors present an enhanced immunogenic phenotype compared to Asiatic and Caucasian tumors. This study is an initial effort to include patients from Hispanic populations in the research of breast cancer etiology and biology to further understand breast cancer disparities.

LINC00460 Is a Dual Biomarker That Acts as a Predictor for Increased Prognosis in Basal-Like Breast Cancer and Potentially Regulates Immunogenic and Differentiation-Related Genes.

Breast cancer (BRCA) is a serious public health problem, as it is the most frequent malignant tumor in women worldwide. BRCA is a molecularly heterogeneous disease, particularly at gene expression (mRNAs) level. Recent evidence shows that coding RNAs represent only 34% of the total transcriptome in a human cell. The rest of the 66% of RNAs are non-coding, so we might be missing relevant biological, clinical or regulatory information. In this report, we identified two novel tumor types from TCGA with LINC00460 deregulation. We used survival analysis to demonstrate that LINC00460 expression is a marker for poor overall (OS), relapse-free (RFS) and distant metastasis-free survival (DMFS) in basal-like BRCA patients. LINC00460 expression is a potential marker for aggressive phenotypes in distinct tumors, including HPV-negative HNSC, stage IV KIRC, locally advanced lung cancer and basal-like BRCA. We show that the LINC00460 prognostic expression effect is tissue-specific, since its upregulation can predict poor OS in some tumors, but also predicts an improved clinical course in BRCA patients. We found that the LINC00460 expression is significantly enriched in the Basal-like 2 (BL2) TNBC subtype and potentially regulates the WNT differentiation pathway. LINC00460 can also modulate a plethora of immunogenic related genes in BRCA, such as SFRP5, FOSL1, IFNK, CSF2, DUSP7 and IL1A and interacts with miR-103-a-1, in-silico, which, in turn, can no longer target WNT7A. Finally, LINC00460:WNT7A ratio constitutes a composite marker for decreased OS and DMFS in Basal-like BRCA, and can predict anthracycline therapy response in ER-BRCA patients. This evidence confirms that LINC00460 is a master regulator in BRCA molecular circuits and influences clinical outcome.

Perivascular epithelioid cell tumor of abdominal origin.

Perivascular epithelioid tumor is not a common disease; therefore, large series are not available in the literature, and most are case reports. Histologic characteristics of these neoplasms are positivity to melanogenic (HMB-45) and muscle stains. All these neoplasms have the characteristic perivascular epithelioid cell or "PEC," but the term myomelanocyte tumor has been proposed because of the immunohistochemistry expression. Females are affected more commonly than males. The uterus seems to be one of the most common organs affected. Its clinical behavior is uncertain, and standard treatment has not been established as well as criteria for malignancy. We report 3 cases of abdominal PEComa, 1 of them with benign clinical outcome and 2 with an aggressive behavior.

A Retrospective Study of a Multi-Center Case Series of 452 Zygomatic Implants Placed Over 5 Years for Treatment of Severe Maxillary Atrophy.

BACKGROUND: Treatment of the severely resorbed maxilla traditionally has been managed with such protocols as sinus elevation, bone and soft-tissue grafting, and osteotomy procedures. The use of zygomatic implants has made it possible to circumvent such procedures, allowing immediate loading of implants with fixed prostheses. OBJECTIVE: This study reports the success rate of 452 zygomatic implants placed and restored in 249 patients over 5 years in a multi-center setting. Additionally, case examples are presented. METHODS: The authors conducted a multi-center case series study. Inclusion criteria were ASA 1 or ASA 2, nonsmoking adults over age 30, fully or partially edentulous, with severely atrophic maxillae. These patients had zygomatic implants placed over a 5-year period with a follow-up of 5 years. The survival rate of these implants is described. RESULTS: A total of 249 patients, aged 34 to 80, had 452 zygomatic implants placed. Survival rate was 95% for quad zygoma; 99.1% for unilateral zygoma with additional premaxillary implants; 98.7% for bilateral single zygoma with additional premaxillary implants; and 100% for unilateral zygoma as a distal extension in implant-supported fixed prostheses. Overall implant survival rate was 97.6%. CONCLUSION: This study supports reports of zygomatic implants having a high success rate while allowing an array of ancillary procedures to be avoided. CLINICAL IMPLICATIONS: The use of zygomatic implants in the atrophic maxilla has shown to be a reliable treatment option for patients selecting to not undergo advanced bone-replacing protocols.

Mitochondrial DNA Mutation Analysis in Breast Cancer: Shifting From Germline Heteroplasmy Toward Homoplasmy in Tumors.

Studies have suggested a potential role of somatic mitochondrial mutations in cancer development. To analyze the landscape of somatic mitochondrial mutation in breast cancer and to determine whether mitochondrial DNA (mtDNA) mutational burden is correlated with overall survival (OS), we sequenced whole mtDNA from 92 matched-paired primary breast tumors and peripheral blood. A total of 324 germline variants and 173 somatic mutations were found in the tumors. The most common germline allele was 663G (12S), showing lower heteroplasmy levels in peripheral blood lymphocytes than in their matched tumors, even reaching homoplasmic status in several cases. The heteroplasmy load was higher in tumors than in their paired normal tissues. Somatic mtDNA mutations were found in 73.9% of breast tumors; 59% of these mutations were located in the coding region (66.7% non-synonymous and 33.3% synonymous). Although the CO1 gene presented the highest number of mutations, tRNA genes (T,C, and W), rRNA 12S, and CO1 and ATP6 exhibited the highest mutation rates. No specific mtDNA mutational profile was associated with molecular subtypes of breast cancer, and we found no correlation between mtDNA mutational burden and OS. Future investigations will provide insight into the molecular mechanisms through which mtDNA mutations and heteroplasmy shifting contribute to breast cancer development.

A lncRNA landscape in breast cancer reveals a potential role for AC009283.1 in proliferation and apoptosis in HER2-enriched subtype.

Breast cancer is the most commonly diagnosed neoplasm in women worldwide with a well-recognized heterogeneous pathology, classified into four molecular subtypes: Luminal A, Luminal B, HER2-enriched and Basal-like, each one with different biological and clinical characteristics. Long non-coding RNAs (lncRNAs) represent 33% of the human transcriptome and play critical roles in breast carcinogenesis, but most of their functions are still unknown. Therefore, cancer research could benefit from continued exploration into the biology of lncRNAs in this neoplasm. We characterized lncRNA expression portraits in 74 breast tumors belonging to the four molecular subtypes using transcriptome microarrays. To infer the biological role of the deregulated lncRNAs in the molecular subtypes, we performed co-expression analysis of lncRNA-mRNA and gene ontology analysis. We identified 307 deregulated lncRNAs in tumor compared to normal tissue and 354 deregulated lncRNAs among the different molecular subtypes. Through co-expression analysis between lncRNAs and protein-coding genes, along with gene enrichment analysis, we inferred the potential function of the most deregulated lncRNAs in each molecular subtype, and independently validated our results taking advantage of TCGA data. Overexpression of the AC009283.1 was observed in the HER2-enriched subtype and it is localized in an amplification zone at chromosome 17q12, suggesting it to be a potential tumorigenic lncRNA. The functional role of lncRNA AC009283.1 was examined through loss of function assays in vitro and determining its impact on global gene expression. These studies revealed that AC009283.1 regulates genes involved in proliferation, cell cycle and apoptosis in a HER2 cellular model. We further confirmed these findings through ssGSEA and CEMITool analysis in an independent HER2-amplified breast cancer cohort. Our findings suggest a wide range of biological functions for lncRNAs in each breast cancer molecular subtype and provide a basis for their biological and functional study, as was conducted for AC009283.1, showing it to be a potential regulator of proliferation and apoptosis in the HER2-enriched subtype.

FAM83H-AS1 is a potential modulator of cancer driver genes across different tumors and a prognostic marker for ER/PR + BRCA patients.

Breast cancer (BRCA) is a serious public health problem, as it is the most frequent malignant tumor in women worldwide. BRCA is a molecularly heterogenic disease, particularly at gene expression (mRNAs) level. Recent evidence shows that coding RNAs represent only 34% of the total transcriptome in a human cell. The rest of the 66% of RNAs are non-coding, so we might be missing relevant biological, clinical or regulatory information. In this report, we identified nine novel tumor types from TCGA with FAM83H-AS1 deregulation. We used survival analysis to demonstrate that FAM83H-AS1 expression is a marker for poor survival in IHC-detected ER and PR positive BRCA patients and found a significant correlation between FAM83H-AS1 overexpression and tamoxifen resistance. Estrogen and Progesterone receptor expression levels interact with FAM83H-AS1 to potentiate its effect in OS prediction. FAM83H-AS1 silencing impairs two important breast cancer related pathways: cell migration and cell death. Among the most relevant potential FAM83H-AS1 gene targets, we found p63 and claudin 1 (CLDN1) to be deregulated after FAM83H-AS1 knockdown. Using correlation analysis, we show that FAM83H-AS1 can regulate a plethora of cancer-related genes across multiple tumor types, including BRCA. This evidence suggests that FAM83H-AS1 is a master regulator in different cancer types, and BRCA in particular.

Significant weight loss in breastfed term infants readmitted for hyperbilirubinemia.

BACKGROUND: Weight loss of greater than 7% from birth weight indicates possible feeding problems. Inadequate oral intake causes weight loss and increases the bilirubin enterohepatic circulation. The objective of this study was to describe the association between total serum bilirubin (TSB) levels and weight loss in healthy term infants readmitted for hyperbilirubinemia after birth hospitalization. METHODS: We reviewed medical records of breastfed term infants who received phototherapy according to TSB levels readmitted to Caja Petrolera de Salud Clinic in La Paz, Bolivia during January 2005 through October 2008. RESULTS: Seventy-nine infants were studied (64.6% were males). The hyperbilirubinemia readmission rate was 5% among breastfed infants. Term infants were readmitted at a median age of 4 days. Mean TSB level was 18.6 +/- 3 mg/dL. Thirty (38%) had significant weight loss. A weak correlation between TSB levels and percent of weight loss was identified (r = 0.20; p < 0.05). The frequency of severe hyperbilirubinemia (> 20 mg/dL) was notably higher among infants with significant weight loss (46.7% vs. 18.4%; p < 0.05). The risk of having severe hyperbilirubinemia was approximately 4 times greater for infants with significant weight loss (OR: 3.9; 95% CI: 1.4-10.8; p < 0.05). CONCLUSIONS: Significant weight loss could be a useful parameter to identify breastfed term infants at risk of severe hyperbilirubinemia either during birth hospitalization or outpatient follow-up visits in settings where routine pre-discharge TSB levels have not been implemented yet.

Maxillary molar distalization with the dual-force distalizer supported by mini-implants: a clinical study.

INTRODUCTION: The objective of this prospective study was to describe the clinical effects of a bone-supported molar distalizing appliance, the dual-force distalizer. METHODS: The study group included 16 patients (mean age, 14.3 years) with Class II molar relationships. Study models and lateral cephalograms were taken before and after the distalizing movement to record significant dental and skeletal changes (Wilcoxon test). RESULTS: The average distalization time was 5 months, with a movement rate of 1.2 mm per month; the distalization amounts were 5.9 +/- 1.72 mm at the crown level and 4.4 +/- 1.41 mm at the furcation level. The average molar inclination was 5.6 degrees +/- 3.7 degrees ; this was less than the amount of inclination generated by bone-supported appliances that use single distalizing forces. The correlation between inclination and distalization was not significant, indicating predominantly bodily movement. The teeth anterior to the first molar moved distally also; the second premolars distalized an average of 4.26 mm, and the incisors retruded by 0.53 mm. CONCLUSIONS: The dual-force distalizer is a valid alternative distalizing appliance that generates controlled molar distalization with a good rate of movement and no loss of anchorage.

Comparison of five artificial skin surface film liquids for assessing dermal bioaccessibility of metals in certified reference soils.

Dermal exposure to metals has previously received less attention than oral/inhalation exposure. Nonetheless, human health risk is significant for certain contaminants and exposure scenarios. The present study aims to (1) characterize two certified reference soils (SQC001, BGS 102); and (2) assess Cr, Ni, Pb, and Zn dermal bioaccessibility via in vitro assays using three synthetic sweat formulations (EN 1811, pH 6.5 (Sweat A), NIHS 96-10, pH 4.7 (Sweat B), and a more complex pH 5.5 formulation containing amino acids (Sweat C)) and two sebum formulations. Metals bioaccessibility in sweat followed Sweat B > Sweat C > Sweat A, attributed to sweat B lower pH. Dermal bioaccessibility in both sebum formulations was lower than 1% for Ni and Pb and below 9% for Cr and Zn, possibly due to low affinity of metals for non-polar lipids. It must be noted that bioaccessible Zn in BGS 102 was higher when extracted with synthetic sebum compared to any of the synthetic sweat formulations. Metal bioaccessibility in sweat was considerably higher for SQC001 (up to 76.6% for Zn using Sweat B) than for BGS 102 (ranging between 0.02 and 1.3% for all elements and all sweat formulations), attributed to higher pH, higher organic carbon, and higher cation exchange capacity of reference soil BGS 102. Sebum formulations spiked with metals generally entailed low metal recovery (except for Zn), which may explain overall low bioaccessibility values for sebum. Sebum and sweat formulation, and soil properties seem to control in vitro dermal bioaccessibility of metals.