Protease inhibitors and carcinoma of the esophagus.
BACKGROUND
Squamous cell carcinoma of the esophagus is endemic in parts of South Africa. Previous case-control studies have shown many associations but no clear etiologic pathway has been established.


METHODS
A case-control study of dietary and social factors was performed for 130 patient/control pairs matched for age, gender, and educational level. Staple diet, consumption of wild vegetables, use of tobacco, and traditional beer consumption were compared between the two groups.


RESULTS
New significant associations were found with the consumption of beans (P = 0.016) and consumption of the full traditional diet of maize, pumpkin, and beans (P = 0.027). Known associations with the consumption of Solanum nigrum (P = 0.018) and with smoking (P = 0.002) were confirmed by multiple regression analysis.


CONCLUSIONS
Solanum nigrum, beans, and pumpkin all contain protease inhibitors. Suppression of protease inhibitors can lead to overexpression of growth factors in the esophagus, resulting in a proliferative and oncogenic drive.
Department of Surgery, Bristol Royal Infirmary, University of Bristol, United Kingdom.
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Sammon
D000328:Adult; D000368:Aged; D016022:Case-Control Studies; D004032:Diet; D004815:Epidermal Growth Factor / Q000378:metabolism; D004938:Esophageal Neoplasms / Q000209:etiology*; D007887:Fabaceae; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010946:Plants, Medicinal; D011480:Protease Inhibitors / Q000009:adverse effects*; D016211:Transforming Growth Factor alpha / Q000378:metabolism; D003313:Zea mays
D011480:Protease Inhibitors; D016211:Transforming Growth Factor alpha; D004815:Epidermal Growth Factor