[Detection of p53 gene alteration in sputum sample and its implications in early diagnosis of lung cancer].
OBJECTIVE
To evaluate the value of detecting point mutation of p53 gene in sputum sample and its validity and reliability as a surveillance index in early diagnosis of lung cancer in suspicious patients.


METHODS
Sputum samples were collected from 54 cases identified as lung cancer and 114 cases as pulmonary benign disease. The polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) was performed for detection of point mutation at exon 5 - 8 of p53 gene and sputum smear also used for each sample.


RESULTS
A detection rate of 55.56% (30/54) in the lung cancer group is significantly higher than that of 1.75% (2/114) in the control (P < 0.001). In the lung cancer group, the sensitivity, specificity, and positive likelihood ratio of p53 alterations as a diagnostic marker of lung cancer were 55.56%, 98.25% and 31.75 respectively. Moreover, the detection rates were 35.19% (19/54) by smears and 55.56% (30/54) by PCR-SSCP-silver stain; both the difference and consistency were statistically significant (P < 0.01 and P < 0.05 respectively). Statistic analysis did not show any significant relation between p53 alteration and clinical parameters such as gender, smoking habits, histotypes and stages, but the detection rate of p53 alteration in older patients (>or=60 years old) was significantly higher than that in younger (P = 0.02). One case with p53 alteration at exon 5 in the control group was confirmed to be squamous carcinoma after 4 years of follow-up.


CONCLUSIONS
Detection of p53 gene alteration in sputum sample by PCR-SSCP-silver stain can be used as a follow-up surveillance index for early diagnosis of lung cancer in suspicious patients.
Wang
B
B
Department of Respiratory Diseases, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing 100730, China.
Li
L
L
Yao
L
L
Liu
L
L
Zhu
Y
Y
D000328:Adult; D000368:Aged; D042241:Early Diagnosis; D005091:Exons / Q000235:genetics; D005260:Female; D016158:Genes, p53 / Q000235:genetics*; D006801:Humans; D008175:Lung Neoplasms / Q000175:diagnosis* / Q000235:genetics; D008297:Male; D008875:Middle Aged; D017354:Point Mutation; D016133:Polymerase Chain Reaction; D018807:Polymorphism, Single-Stranded Conformational; D016622:Silver Staining; D013183:Sputum / Q000378:metabolism*