BACKGROUNDIt is known that chromium is an inhaled carcinogen and an important risk factor in the development of lung carcinoma.METHODSThe authors used a microscopic X‐ray fluorescence analyzer with transmitted X‐ray mapping imaging (Horiba, Kyoto, Japan) to measure the accumulation of chromium in 10 resected lung tissue specimens and 90 biopsy specimens from chromate workers.RESULTSThe maximum chromium accumulation (mean ± standard deviation) in 10 resected lung tissue specimens was 197 ± 238 counts per second (cps)/mili ampere (mA) (range, 4–649 cps/mA). Chromium accumulation was scattered in six tissue specimens and diffuse in one specimen. Chromium accumulation in the proximal bronchi was less than in the bronchioles or subpleural regions of the lung. Chromium accumulation was detectable in 63 (70%) of 90 biopsy specimens, and the mean accumulation was 6.5 ± 9.2 cps/mA (range, 0–46.5 cps/mA). Chromium detected in bronchial tissue specimens was deposited in the bronchial stroma but not in the epithelium. The maximum chromium accumulations in dysplasic (n = 3), squamous metaplastic (n = 10), and normal bronchial epithelia (n = 9) in chromate workers and in normal bronchial epithelia (n = 3) in non‐chromate workers were 20.2 ± 5.4, 18.3 ± 12.2, 13.2 ± 13.4, and 3.0 ± 1.8 cps/mA, respectively. The amount of chromium accumulation significantly increased according to the progression of malignant change of the bronchial epithelium (P = 0.003).CONCLUSIONSPrevious studies found that lung carcinoma with chromate exposure exhibited a variety of genetic abnormalities. Considering genetic aberrations and chromium accumulation in these premalignant lesions is useful for elucidating the process of carcinogenesis in chromium‐induced lung carcinoma. Cancer 2003. © 2003 American Cancer Society.

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sA significant association was reported between a single nucleotide polymorphism (SNP; AB604331, g. 420 C > A) in the cholecystokinin type A receptor gene and growth traits in some Japanese slow-growing chickens. Demonstration tests of the genetic improvement effect by comparing the superior allele-A fixed chickens with conventional ones were carried out considering the effect of different seasons on growth traits in other slow-growing chickens. Meat-type Okumino-kojidori chickens from Gifu Prefecture are a three-way cross of Gifu-jidori improved, White Plymouth Rock, and Rhode Island Red breeds. We used a total of 468 meat-type Okumino-kojidori: 264 individuals from a private hatchery as conventional chickens and 204 A-allele fixed individuals from the Gifu Prefectural Livestock Research Institute as improved chickens. We performed fattening experiments over two seasons: summer and winter. In each season, experimental birds of both sexes were hatched on the same day, raised in the same chicken house, and fed the same diet ad libitum for 12 weeks. Body weight was recorded at 3, 6, 9, and 12 weeks of age. SNP genotypes were determined using the mismatch amplification mutation assay. Association between the SNP and growth traits was analyzed using generalized linear models built on sex-based, seasonal, additive, and dominance genetic effects. The observed AA, AC, and CC genotype frequencies in the conventional chickens were 0.158, 0.479, and 0.363, respectively; body weight at 12 weeks and average daily gain from 3 to 12 weeks was superior for the A allele compared to the C allele. The improved chickens were heavier than the conventional ones at 12 weeks. Body weight at 12 weeks in allele-A fixed chickens increased by 3.2% compared to the conventional chickens. We concluded that g. 420 C > A is a good selective marker that increases slaughter weight in the meat-type Okumino-kojidori chickens.

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