Serum anti-p53 autoantibodies from patients with idiopathic pulmonary fibrosis associated with lung cancer

Mutations of the tumour suppressor gene p53 lead to accumulation of the mut ated p53 protein and subsequent production of antoantibodies against p53 pr oteins, which are also detected in lung cancer. Lung cancer is frequently a ssociated with idiopathic pulmonary fibrosis (IPF). Therefore, we hypothesi zed that there might be a relationship between the p53 mutation and high pr evalence of lung cancer in IPF. To test this hypothesis, we measured serum p53 antibody levels by an ELISA in various lung diseases including lung can cer (n=98), IPF (n=46; with lung cancer, n=14 and without lung cancer, n=32 ), pulmonary emphysema (PE, n=23) and healthy controls (HC, n=93). The medi an values of the serum anti-p53 antibody in each group were 8.78, 9.18, 8.0 8 and 4.95 for patients with lung cancer, IPF with lung cancer, IPF without lung cancer and PE, respectively, and 2.2 for the healthy control group. T he groups of IPF (with and without lung cancer) showed a similar level of m edian values to the lung cancer group and a tendency for a higher level tha n the PE group. When the cut-off value was set at 7.7 according to the 95% specificity level for normal control, the incidence of positive anti-p53 an tibody was significantly higher in lung cancer (61.2%), IPF with lung cance r (57.1%) and IPF without lung cancer (53.1%) than PE (21.7%). These result s suggest that p53 mutations occur frequently and substantially in IPF, res ulting in a high prevalence of lung cancer.