23 April 2009
The association between phenotype and size of breast tumors induced by 1-methyl-1-nitrosourea (MNU) injection in rats
Hasnan JaafarABCDEFG, Fauziah Mohamad IdrisADEF, Siti Norasikin Mohd NafiBCEFMed Sci Monit 2009; 15(5): BR129-134 :: ID: 869635
Abstract
Background
Administration of 1-methyl-1-nitrosourea (MNU) is considered a simple and rapid method for inducing breast tumors in rats. While most studies focus on the time frame of tumor development, there are little data on the development of breast tumor in relation to tumor size. Thus the current study was carried out to analyze the phenotype of MNU-induced tumors in relation to tumor size.
Material and Method
Twenty-one 21-day-old female Sprague Dawley rats were administered intraperitoneally with MNU at a dose of 70 mg/kg body weight. The entire palpable tumor was excised when the tumor size reached the diameters of 4.0+/-0.5 mm, 8.0+/-0.5 mm, 12.0+/-0.5 mm, and 16.0+/-0.5 mm and then subjected to histopathological assessment.
Results
Epithelial inclusion cysts and mammary adenomas made up most of the benign tumors, with four cases occurring together with malignant lesions. Ductal carcinoma in situ was seen in tumor sizes of 4.0+/-0.5 mm or less. Among the malignant tumors, the cribriform type was seen predominantly at tumor sizes of less than 12.0+/-0.5 mm, while those with sizes of 12.0+/-0.5 mm or greater were of papillary type. Infiltrating ductal carcinoma-no special type (IDC-NST) commonly seen in humans was also observed at tumor sizes greater than 12.0+/-0.5 mm.
Conclusions
The tumors were found to be mainly of malignant type and the histological features of the induced tumors underwent changes as the tumor grew in size.
Keywords: Phenotype, Methylnitrosourea - toxicity, Mammary Neoplasms, Experimental - pathology, Carcinogens - toxicity
Editorial
01 April 2024 : Editorial
Editorial: Forty Years of Waiting for Prevention and Cure of HIV Infection – Ongoing Challenges and Hopes for Vaccine Development and Overcoming Antiretroviral Drug ResistanceDOI: 10.12659/MSM.944600
Med Sci Monit 2024; 30:e944600
In Press
06 Mar 2024 : Clinical Research
Comparison of Outcomes between Single-Level and Double-Level Corpectomy in Thoracolumbar Reconstruction: A ...Med Sci Monit In Press; DOI: 10.12659/MSM.943797
21 Mar 2024 : Meta-Analysis
Economic Evaluation of COVID-19 Screening Tests and Surveillance Strategies in Low-Income, Middle-Income, a...Med Sci Monit In Press; DOI: 10.12659/MSM.943863
10 Apr 2024 : Clinical Research
Predicting Acute Cardiovascular Complications in COVID-19: Insights from a Specialized Cardiac Referral Dep...Med Sci Monit In Press; DOI: 10.12659/MSM.942612
06 Mar 2024 : Clinical Research
Enhanced Surgical Outcomes of Popliteal Cyst Excision: A Retrospective Study Comparing Arthroscopic Debride...Med Sci Monit In Press; DOI: 10.12659/MSM.941102
Most Viewed Current Articles
17 Jan 2024 : Review article
Vaccination Guidelines for Pregnant Women: Addressing COVID-19 and the Omicron VariantDOI :10.12659/MSM.942799
Med Sci Monit 2024; 30:e942799
14 Dec 2022 : Clinical Research
Prevalence and Variability of Allergen-Specific Immunoglobulin E in Patients with Elevated Tryptase LevelsDOI :10.12659/MSM.937990
Med Sci Monit 2022; 28:e937990
16 May 2023 : Clinical Research
Electrophysiological Testing for an Auditory Processing Disorder and Reading Performance in 54 School Stude...DOI :10.12659/MSM.940387
Med Sci Monit 2023; 29:e940387
01 Jan 2022 : Editorial
Editorial: Current Status of Oral Antiviral Drug Treatments for SARS-CoV-2 Infection in Non-Hospitalized Pa...DOI :10.12659/MSM.935952
Med Sci Monit 2022; 28:e935952