Carcinogenic Mechanisms of Hexavalent Chromium: From

Overview

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Key numbers

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• treatment options (2), leading to a 5-year survival rate of only 26.6% (3). Lung cancer is a
• 4 categories as shown in Table 1: Lung cancer endpoints, DNA double strand breaks,
• endpoints of hexavalent chromium in humans (Table 2, 3, S1), animal (Table 4 and S2) and
• of studies reported respiratory cancers in Cr(VI)-exposed individuals (Table 2). Regarding
• 3, while other effects are also summarized and detailed in Table S1. For example, Seçin
• at mononucleotide repeats of RAD50 were increased by 16% in chromate lung cancer
• (51–54). From these, 3 studies, exposing animals to welding fumes (3.6% Cr content) or
• thermal spray fumes (56% Cr content) (52), different chromate compounds (51) or Cr(VI)
• All the studies reviewed in Tables 5 and S3 showed Cr(VI) exposure induces neoplastic
• soft agar formation assay (Table 5), which measures the ability of cells to grow in an
• xenograft assays (Table 5). The majority of the cell culture studies focused on soluble Cr(VI)
• studies assessing DNA double strand break endpoints in human (Tables 6 and S4), animal
• summarized them in Tables 6 and S4. Specifically, one study measured DNA–protein
• a method that measures only DNA double strand breaks (Tables 7 and S5). From all these
• indirectly, studies summarized in Tables 8 and S6 show Cr(VI)-induced breaks occur in
• with 70–80% of all malignancy characterized as aneuploid. Thus, aneuploidy is considered
• to a more aggressive and less treatable cancer (129). There are several mechanisms for the
• studies (Tables 9 and S7), animal studies (Tables 10 and S8) and cell culture (Tables 11 and
• showed Cr(VI) increases markers of aneuploidy (Tables 9 and S7). This study used MN-
• 137. and both show Cr(VI) causes aneuploidy (Tables 10 and S9). The first study,
• Endpoints considering clastogenicity in humans (Tables 9 and S7), animals (Tables 10 and
• exposed to Cr(VI) (Tables 9 and S7). Out of 4 studies, 3 studies have evaluated structural
• (138) one that considered male and female rats (136) (Tables 10 and S8). The animal
• intraperitoneal injection. BDF1(C57BLXDBA2) male mice were administered 50 mg/kg
• and female Wistar rats to 0, 0.4, 0.8 mg/kg zinc chromate once a week for 90 days by
• 0.8 mg/kg zinc chromate induced an average of 4.4, 9.7 and 11 total chromosome damage.
• 181. Reynolds M, et al. Undetectable role of oxidative DNA damage in cell cycle, cytotoxic and
• ranged from cities) no Cr (VI) ranges to F 1248 cases of
• designated as 59 ranged from diagnosed. From
• Cr(VI) OR M (median Europe and 20965 controls. 16901 lung Most were Most were M unexposed M exposed Men have increased (17)
• chromate range from controls (from controls (from between 45 between Cr(VI) exposure
• exposure <1.5 y, 1.5– Table 1) Table 1) and 64 45 and 65 or nickel exposure
• Population Rates Referent 1940 (age Population over 200 ug/L Cr-
• 200 ug/L Cr-years
• Nickel and at least 6 United general 1762 workers general Age range general 812 M and Significantly (27)
• age-adjusted was 23.3% of all
• Observed/ Chromate Mean years Baltimore, Non lung cancer Lung cancer Average age Average M M Cumulative Cr(VI) (34)
• Proportionate Smelter Range from New jersey US general 3408 workers US general not US general Abundancy: There were 1279 (35)
• percentage alloy work, 10.02 (1–41 Republic cases in non cases in mean 65.71 onset, significantly
• (onset/ chromate y) exposed people chromate (43–87) mean 62.2 decreased the age
• alloy work, (1–41y) Republic cases in non cases in mean 65.7 onset, significantly
• chromate exposed people chromate (43–87) mean 62.2 decreased the age

Methods (brief)

• samples compared to non-chromate lung cancers. This last study also investigated the
• with alkaline comet assay in blood samples from male Swiss albino mice exposed through
• FISH method in blood samples from welders, and showed that welders had more MN with
• measured aneuploid metaphases using chromosome analysis assay in blood samples from
• Another study Benova et al., (131) measured chromosome aberrations in blood samples of
• chromosome instability in lymphocytes collected from blood. Concentrations of 0, 0.4 and
• Hudson County soil sample heavily contaminated with hexavalent chromium. Arch Environ Health
• Samples: 38 lung and one was small
• lung cancers (environmental samples samples values (99%
• damage, production RAD50, DNA-PKs analysis chromate lung cancer samples, and none in nonchromate lung cancers
• Micronucleus (MN) PBL Stainless-steel welding, bath Blood samples were collected on Significantly higher levels were found in exposed group compared to control. (135)
• in blood chromate mg/kg aspiration increase in chromosome instability in lymphocytes collected

Implications

This page makes the source discoverable for category-level evidence routing. Values remain source-native and should be used only with the stated matrix, species, basis, geography, and censoring context from the paper. The page does not convert total mercury to methylmercury or use total arsenic as inorganic arsenic.

Wiki pages this source may touch

• Fish — marine, non-predatory (sardines, anchovies, salmon, cod)
• Cadmium
• Arsenic
• Nickel
• Chromium

Verification notes

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Update history

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