Serum ras (p21) as a marker for occupationally derived lung cancer?

Our plain-English summary of Serum ras (p21) as a marker for occupationally derived lung cancer?, by J. Schneider, P. Presek, A. Braun, et al (Clinical Chemistry and Laboratory Medicine, 2000).

The study

• Authors: J. Schneider, P. Presek, A. Braun, S. Löffler, H.J. Woitowitz
• Journal: Clinical Chemistry and Laboratory Medicine
• Published: 2000;38(4):301-5
• Cited by: 5 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Certain subsets of the population are especially sensitive to carcinogens, and this can be determined using molecular biological methods. In the literature there has been evidence presented for the use of p21ras (ras) as a tumor marker for human carcinogenic substances such as asbestos, polycyclic aromatic hydrocarbons, and vinyl chloride in the workplace. In this study we have examined whether serum ras could serve as a biomarker for the early detection of occupationally derived lung cancer, with an emphasis on Schneeberger (radon-induced) lung cancer. Sera were taken from 65 male tumor patients. Fifty-nine patients suffered from primary lung cancer (including 18 patients with Schneeberger lung cancer and 12 patients with asbestos-related lung cancer). Additionally, 29 patients with non-malignant lung disease, and a healthy control group (44) including 32 former uranium miners of SDAG Wismut exposed to ionizing radiation (radon and its decay products) were examined. Ras protein was determined via three different methods: 1) immunoprecipitation followed by SDS-polyacrylamide gel electrophoresis (SDS-PAGE) and Western blotting; 2) SDS-PAGE using 5-17% gradient gels followed by Western blotting; 3) pre-incubation with Blue Sepharose, SDS-PAGE on 5-17% gradient gels, and Western blotting. The results show that 1 ng ras protein was measurable in serum standards. This protein could not be detected in patient sera or in sera from any of the study groups. Thus, ras cannot be considered useful as a marker for the early detection of asbestos-induced or Schneeberger lung cancer.

In plain English

This laboratory study tested whether a protein called ras (p21), measured in blood serum, could serve as a marker for early detection of lung cancer linked to work. Its emphasis was radon-induced (Schneeberger) lung cancer in former uranium miners of SDAG Wismut. The authors examined 138 serum samples from men. There were 65 tumor patients: fifty-nine with primary lung cancer, of whom 29 were long-time cigarette smokers without other relevant occupational exposure, 18 were former uranium miners and 12 had asbestos-related lung cancer. There were also 29 patients with non-malignant lung disease, 4 of them with asbestosis, and 44 healthy controls, 32 of them former uranium miners. Three laboratory methods were used. Ras was not detected in any serum sample, although ras added to control serum was detectable at 1 ng with the second method. With the first method, recovery of added ras from serum was very low. The authors concluded that ras is not a useful marker of early effects of occupational disease due to asbestos or of radon-induced lung cancer.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Laboratory study measuring a protein (ras, p21) in stored blood serum samples from several patient and control groups, using three different detection methods
• Who was studied: 138 serum samples from male subjects of a German multicenter study on radiation-induced illness in former uranium miners of SDAG Wismut. Groups: 65 tumor patients (fifty-nine with primary lung cancer plus six with lung metastases of tumors from outside the lung); 29 patients with non-malignant lung disease (4 with asbestosis, 25 with interstitial fibrosis without relevant asbestos exposure); and 44 healthy controls, including 32 former uranium miners exposed to ionizing radiation.
• Exposure: Among the lung cancer patients: 29 long-time cigarette smokers without relevant exposure to other known occupational lung carcinogens; 18 former uranium miners exposed to ionizing radiation (radon and its decay products) from uranium mining or processing; and 12 patients with asbestos-related lung cancers as defined in the list of occupational diseases. No asbestos fiber type is specified.
• Main results:
  • Method 1 (immunoprecipitation, SDS-PAGE and Western blotting): ras was not found in any serum sample.
  • With method 1, recovery of ras added to serum was very low and did not depend on the amount added (data not shown).
  • Method 2 (sera run directly on gradient gels, then Western blotting): ras was not detected in any serum sample, although ras added to control serum was detectable at 1 ng.
  • Method 3 (pre-incubation with Blue Sepharose, then gradient gels and Western blotting): naturally present ras was not detected in any patient sample, including sera from lung cancer patients and from healthy former uranium miners.
• The authors' conclusion: The authors concluded that ras is not a useful marker of early effects of occupational diseases due to asbestos or of radon-induced (Schneeberger) lung cancer. They wrote that its routine use as a diagnostic or prognostic tool, or for telling occupational from non-occupational causes, cannot be recommended at present.
• Limitations the authors state:
  • The authors noted that method 2 could analyze only 10 microliters of serum because of serum albumin. Method 3 was an attempt to remove albumin so that more serum could be loaded.

Topics

The National Library of Medicine indexes this study under subjects our site covers: Lung cancer.

Medical terms in this study, explained in our Lexicon: Lung Cancer, Tumor Marker, Carcinogenic, Biomarker.

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