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skin cancer could bear some relation to work in the manufacture ofpolyvinyl chloride. [Langard S et al; Occup Environ Med 57 (1): 65-68(2000)]**PEER REVIEWED**The production of mutations in cellular oncogenes such as ras is involvedin the development of many human cancers. These mutations result in theexpression of mutant forms of the encoded p21 protein which canpotentially serve as a biomarker for this carcinogenic process. Workersexposed to vinyl chloride (VC) who are at risk for the development of thesentinel neoplasm angiosarcoma of the liver (ASL) represent a modelpopulation for the study of such a mutant p21ras biomarker, since VC isknown to cause a specific ras mutation in ASL. To determine therelationship between VC exposure &amp; this biomarker, serum samples froma cohort of 225 French VC workers &amp; 111 age-sex-race-smoking-drinkingmatched unexposed controls were examined for the presence of mutant p21rasby immunoblotting with a mouse monoclonal antibody specific for the mutantprotein. Stratifying the exposed workers by degree of VC exposure inestimated ppm-years by quartiles yielded a statistically significant trendfor increasing odds ratio for sero-positivity of the p21ras biomarker withincreasing exposure. These results suggest that this serum biomarker isrelated to VC exposure and may be an early indicator of carcinogenic riskin exposed individuals. [LI Y et al; BIOMARKERS 3 (6): 433-439(1998)]**PEER REVIEWED**Vinyl chloride (VC) workers are known to be at risk for development ofangiosarcoma of the liver (ASL), a rare tumor. Previously, a study of p53gene mutations in tumors of VC-exposed workers found that 50% of liverangiosarcomas contained such mutations. Mutant p53 oncoprotein &amp;anti-p53 antibodies can also be found in the sera of ASL patients &amp;VC-exposed workers without cancer. ... In this study, we usedenzyme-linked immunosorbent assays to detect mutant p53 protein &amp;anti-p53 antibodies in the plasma of VC-exposed workers in Taiwan.Thirty-three of 251 (13.2%) VC-workers tested positive for the p53overexpression (10% with positive mutant p53 protein &amp; 3.6% withpositive anti-p53) in their plasma, but only 2 of 36 controls (5.6%)tested positive (2.8% with positive mutant p53 protein &amp; 2.8% withpositive anti-p53). There was a significant association between cumulativeVC exposure concn &amp; positive p53 expression ... among VC workers afterwe adjusted for age, hepatitis, drinking, &amp; smoking status. Insummary, P53 overexpression (mutant p53 protein or anti-p53 antibody) canbe found in the plasma of VC workers in Taiwan, &amp; a significantdose-response relationship exists between plasma p53 overexpression &amp;VC cumulative exposure concn. [Luo JC et al; J Occup Environ Med 41 (6):521-526 (1999)]**PEER REVIEWED**Vinyl chloride (VC) workers are known to be at risk for development ofliver angiosarcoma, a rare tumor. Previously, more than 80% of VC workerswith liver angiosarcoma have been found to have an Asp-13 c-Ki-rasoncogene mutation, &amp; more than 50% of VC-exposed workers without livertumors were found to have Asp13-Ki-ras oncoprotein in their plasma. ... Inthis study, we used enhanced chemiluminescence Western blotting to detectAsp13-p21-Ki-ras in the sera of VC-exposed workers in Taiwan. There were14 of 113 (12.4%) VC workers positive for the Asp13-Ki-ras oncoprotein inplasma, but 0 of 18 controls were positive. There were 10 of 69 (14.5%)plasma-positives among the more highly exposed ( > 1000 ppm-months)workers &amp; 4 of 48 (9.1%) plasma-positives among the lesser exposed( < or = 1000 ppm-months). Compared with the unexposed controls, the