Lung Cancer With Special Reference To Experimental Aspects

Our plain-English summary of Lung Cancer With Special Reference To Experimental Aspects, by W.E. Smith (1952).

The study

• Author: W.E. Smith
• Published: Archives Of Industrial Hygiene 5(3):209-217, March (1952)
• Type of article: Journal article
• Our copy: from Johns-Manville's own medical library, J-M no. 002654. The article is still under copyright, so we describe it here rather than post it.

In plain English

This article was a 1949 lecture to a cancer prevention committee in New York. It mainly reviewed past animal experiments on lung cancer. It also described the author's own experiments, in which mouse embryo lung tissue implanted with chemical carcinogens yielded several types of carcinoma. One reviewed experiment, by Nordmann and Sorge, exposed mice to asbestos dust of unstated fiber type and particle size. Of an original 100 mice, those researchers reported one squamous cell carcinoma and one adenocarcinoma. The author argued that the 'squamous cancer' photograph almost certainly showed only metaplasia, and that the unillustrated adenocarcinoma is a type that can arise spontaneously in mice. In the author's opinion, the experiment gave no evidence that asbestos dust causes tumors, and instead appeared to show it did not cause lung tumors under the conditions used. The author credited Andervont with the first undoubted experimental squamous cell lung cancer, in mice in 1937. The author concluded that mouse lung adenomas have limited bearing on the tumor types behind the great majority of human lung cancers. The damaged scan ends partway through the conclusions.

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: Narrative review given as a lecture (address to a cancer prevention committee) on experimental studies of lung cancer in animals, with the author's own tissue-transplant experiments and observations on mouse lungs
• Who was studied: Mainly published animal experiments (mice, also rats, rabbits, guinea pigs and sheep) on inducing lung tumors, plus the author's own experiments with mouse embryo lung tissue and examination of lungs from young mice of the C, A and C57 strains
• Exposure: Various agents in the reviewed experiments, including tar, tobacco smoke, city soot, chemical carcinogens (methylcholanthrene, dibenzanthracene), urethan, and asbestos dust (fiber type not named) inhaled by mice in the Nordmann and Sorge experiment
• Main results:
  • In the reviewed Nordmann and Sorge experiment with asbestos dust in mice (original group of 100 mice), squamous cell carcinoma was reported in 1 animal and adenocarcinoma in 1
  • The particle size of the asbestos dust in that experiment was not stated, though asbestos fibers were found in the lungs
  • The author judged that the photograph offered for the one 'squamous cancer' almost certainly represented only squamous cell metaplasia. The author also noted that the reported adenocarcinoma was not illustrated and is a type that can arise spontaneously from the common mouse adenoma.
  • In the author's opinion, the Nordmann and Sorge experiment did not afford evidence that asbestos dust can provoke tumors. It appeared instead to show that asbestos dust did not provoke lung tumors under the test conditions used.
  • The author credited Andervont with the first undoubted experimental production of a squamous cell carcinoma of the lung, in mice in 1937, using threads coated with a chemical carcinogen
  • In the author's own earlier experiments (the tissue-transplant technique), mouse embryo lung tissue implanted with methylcholanthrene or dibenzanthracene yielded squamous cell, transitional cell, anaplastic and alveolar cell carcinomas, confirmed by transplantation to other hosts
  • In the author's own serial sections of lungs from young C57 mice, the author had so far not found cell groups that could be regarded as early adenomas
• The authors' conclusion: The author concluded that the pulmonary adenoma of mice is a specialized situation with limited bearing on the types of tumors that account for the great majority of human lung cancer. A further concluding statement about animal lung cancer is cut off in the scan and cannot be read in full.
• Limitations the authors state:
  • The author described the tissue-transplant technique as a very artificial procedure that could at best serve only as a screening method
  • The author stated that the data on early adenoma-like cells in young mice were limited

Topics

Medical terms in this study, explained in our Lexicon: Lung Cancer, Carcinoma, Squamous Cell Carcinoma, Adenocarcinoma.

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