Sputum cytology can identify lung carcinoma risk

14 January 2005

The degree of anthracosis and abnormal DNA methylation detected in sputum contents can be helpful in identifying those at risk of lung cancer, Japanese researchers report in the December 25th issue of Cancer Cytopathology.

As senior investigator Dr. Masayuki Noguchi told Reuters Health, "calculation of anthracotic index (AI) and detection of abnormal methylation cannot be used to definitely find cancer, but provide very useful additional information to screen a population at risk of lung carcinoma."

Dr. Noguchi of the University of Tsukuba, Ibaraki, and colleagues studied 356 sputum specimens from 210 patients. Eight-seven of the patients had lung cancer.

AI was significantly higher in patients with lung cancer.

In addition, abnormal methylation of the p16 gene was seen in 21.7% of specimens from cancer patients. Abnormal methylation of the adenomatous polyposis coli and retinoic acid receptor-beta genes was seen in 28.2% and 26.9% of cancer patients, respectively.

These ratios were significantly higher than those in samples from subjects without lung cancer. For these subjects, no abnormal methylation was seen in the p16 gene. In the other genes, abnormalities ranged from 3.9% to 7.6%.

The investigators conclude that AI and abnormal methylation in sputum cytology provide "reliable, independent markers for identifying persons at high risk of lung carcinoma."

(Source: Cancer (Cancer Cytopathol) 2004;102:348-354: Reuters Health: Oncolink: January 2005.)