Characterization of solid tumors induced by polycyclic aromatic hydrocarbons in mice.
BACKGROUND
To assess the effects of single polycyclic aromatic hydrocarbons (PAHs) on solid tumor initiation, and investigate their roles in immune response regulation.


METHODS
Mice (100) were randomly divided into 5 groups (n=20) to be intraperitoneally injected with 10 daily doses of DMSO (control), anthracene (50 mg/kg), benzo-(a)-pyrene (10 mg/kg), benzo-(a)-pyrene (20 mg/kg), and benzo-[G, H, I])-perylene (5 mg/kg), respectively. Three months later, serum IL-2 and IL-6 levels were assessed by ELISA; liver, kidney, stomach and lung tissues were subjected to histopathological examinations.


RESULTS
Liver cancer incidences after benzo-[G, H, I]-perylene, benzo-(a)-pyrene (10 mg/kg), benzo-(a)-pyrene (20 mg/kg), and anthracene were 21.1, 26.3, 35.3, and 27.8%, respectively; 21.1, 0, 41.2, and 0% showed stomach cancer, respectively; 0, 0, 11.8 and 0% displayed kidney cancer, respectively. The occurrences of precancerous liver lesions for benzo-[G, H, I]-perylene, benzo-(a)-pyrene (10 mg/kg), benzo-(a)-pyrene (20 mg/kg) and anthracene groups, respectively, were 68.4, 73.7, 64.7, and 55.6%; 78.9, 68.4, 29.4, and 27.8% showed precancerous stomach lesions, while 42.1, 47.4, 58.8, and 33.3% had precancerous kidney lesions; respectively. No obvious lung lesions were found in any group. Serum IL-2 and IL-6 levels in treatment groups were significantly lower compared with control values (P<0.01).


CONCLUSIONS
PAHs induce cancer and precancerous lesions in the liver, stomach, and kidney. Benzo (a) pyrene initiates gastric cancer in a dose-dependent manner, but does not induce precancerous lung lesions. Lower IL-2 and IL-6 levels in treatment groups compared with controls suggest that PAHs cause overt immune inhibition.
Clinical College, GanSu University of Chinese Tranditional Medicine, Lanzhou, Gansu, China (mainland).
Qiulan
Q
Wang
Department of Pathology, San Ai Tang Hospital, Lanzhou, Gansu, China (mainland).
Yongjie
Y
Xue
D000818:Animals; D006652:Histological Techniques; D007376:Interleukin-2 / Q000276:immunology; D015850:Interleukin-6 / Q000276:immunology; D007680:Kidney Neoplasms / Q000139:chemically induced* / Q000276:immunology / Q000473:pathology*; D008113:Liver Neoplasms / Q000139:chemically induced* / Q000276:immunology / Q000473:pathology*; D051379:Mice; D011084:Polycyclic Aromatic Hydrocarbons / Q000633:toxicity*; D013274:Stomach Neoplasms / Q000139:chemically induced* / Q000276:immunology / Q000473:pathology*
D007376:Interleukin-2; D015850:Interleukin-6; D011084:Polycyclic Aromatic Hydrocarbons