Keratin expression in chemically induced mouse lung adenomas.

Area of Science:

• Oncology
• Cell Biology
• Toxicology

Background:

• Chemically induced lung tumors in A/J mice display distinct morphological patterns, including alveolar, solid, and papillary types.
• Understanding the cellular origin of these tumors is crucial for deciphering carcinogenesis mechanisms.

Purpose of the Study:

• To investigate the expression of low- and high-molecular-weight cytokeratins in chemically induced lung tumors in A/J mice.
• To determine the cellular origin of papillary lung tumors by analyzing cytokeratin profiles.

Main Methods:

• Induction of lung tumors in A/J mice using benzo(a)pyrene (BP) or N-nitrosoethylurea (ENU).
• Immunohistochemical examination of tumor tissues for the expression of low- and high-molecular-weight cytokeratins.

Main Results:

• Low-molecular-weight cytokeratins were present in all epithelial cells of normal lung and all tumor types.
• High-molecular-weight cytokeratins were exclusively found in normal bronchiolar cells and papillary tumor cells.
• Alveolar/solid tumors did not express high-molecular-weight cytokeratins.

Conclusions:

• The expression pattern of cytokeratins supports the hypothesis that chemically induced papillary lung tumors in A/J mice originate from bronchiolar Clara cells.
• Cytokeratin analysis serves as a valuable tool for tracing the cellular lineage of chemically induced lung tumors.