Open AccessIntraluminal Epidermal Growth Factor Affects Growth of N‐Methyl‐N‐nitrosourea‐initiated Rat Bladder Carcinoma
Author(s) -
Kawai Koji,
Kawamata Hitoshi,
Kameyama Shuji,
Rademaker Alfred,
Oyasu Ryoichi
Publication year - 1995
Publication title -
japanese journal of cancer research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.035
H-Index - 141
eISSN - 1349-7006
pISSN - 0910-5050
DOI - 10.1111/j.1349-7006.1995.tb03075.x
Subject(s) - epidermal growth factor , saline , urinary bladder , population , transitional cell carcinoma , epidermal growth factor receptor , urinary system , ratón , carcinoma , transitional cell , pathology , medicine , endocrinology , cancer research , biology , urology , bladder cancer , cancer , receptor , environmental health
To confirm our recent finding that epidermal growth factor (EGF) appeared to contribute to the tumor‐enhancing effect demonstrated by normal rat urine, we conducted 2 experiments using our heterotopically transplanted rat urinary bladder model. In experiment 1, after a single dose (0.25 mg) of N‐methyl‐N‐nitrosourea (MNU), we intravesically administered EGF (0.5 ml of 500 ng/ml phosphate‐buffered saline) once a week for 30 weeks. Instillation of EGF induced a significantly larger number of tumors than did instillation of the vehicle ( P =0.03). EGF without MNU initiation did not induce tumors. In experiment 2, 2 groups received instillation of killed Escherichia coli (5 × 10 8 cells)/0.5 ml phosphate‐buffered saline once a week for 4 weeks to expand the MNU‐initiated cell population. Subsequent EGF treatment significantly increased the incidence of tumors ( P =0.01). In the groups which did not receive killed E. coli , EGF treatment induced a significantly higher number of tumors than did vehicle treatment ( P <0.001). All of the tumors were low‐grade, superficial transitional cell carcinomas. These observations indicate that EGF acts as a growth‐stimulating factor on dormant neoplastic cells and thereby increases the number of tumors.