Detection of p53 gene mutations in sputum samples and their implications in the early diagnosis of lung cancer in suspicious patients

Chin Med J (Engl). 2001 Jul;114(7):694-7.


Objectives: To evaluate the value of detecting p53 gene point mutations in sputum samples and its validity and reliability as a surveillance index in the early diagnosis of lung cancer in suspicious patients.

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

Results: The detected mutation rate of 55.56% (30/54) in the lung cancer group was significantly higher than that of 1.75% (2/114) in the control group (P < 0.001). In the lung cancer group, the sensitivity, specificity, and positive likelihood ratio (PLR) of p53 mutations as a diagnostic marker for lung cancer were 55.56%, 98.25% and 31.75%, respectively. Also, the detection rates were 35.19% (19/54) by smears and 55.56% (30/54) by PCR-SSCP-silver stain, respectively. The differences both in rate and consistency were statistically significant (P < 0.01 and P < 0.05, respectively). Moreover, statistical analysis showed no significant relations between p53 mutations and clinical parameters such as gender, smoking habits, histotypes and stages, but the detection rate of p53 mutations in older patients (> or = 60 years old) was significantly higher than that in younger patients (P = 0.02). One case with p53 mutations at exon 5 in the control group was confirmed to be squamous cell carcinoma after 4 years of follow-up.

Conclusion: Detection of p53 gene alterations in sputum samples by PCR-SSCP-silver stain can be used as a follow-up surveillance index for the early diagnosis of lung cancer in suspicious patients.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Exons
  • Female
  • Genes, p53*
  • Humans
  • Lung Neoplasms / diagnosis*
  • Male
  • Middle Aged
  • Point Mutation*
  • Polymerase Chain Reaction
  • Polymorphism, Single-Stranded Conformational
  • Sputum / metabolism*