Amplified expression of p21 ras protein in hormone-dependent mammary carcinomas of humans and rodents.

Abstract

Western blotting analysis was utilized to determine the amount of a ras oncogene product, p21 present in mammary carcinomas of humans and rats. The levels of p21 in hormone-dependent rat tumors was about 7-fold that of hormone-independent tumors. The majority of human breast carcinomas examined had high p21 levels, about 10-fold that of the normal breast tissue; 70% of these tumors were estrogen and progesterone receptor positive. p21 levels in the remaining tumors were 3-fold that of the normal breast tissue, regardless of the receptor status. Fibroadenomas and fibrocystic disease showed p21 levels similar to that of the normal mammary glands. Moreover, the high p21 levels in the mammary carcinomas correlated directly with high GTPase activity, as revealed by the photo-incorporation of 8-N3-[gamma-32P]GTP into the tumor lysates. The results suggest that hormone-dependency of mammary carcinomas may correlate with quantitative change in 'normal' p21 protein.

• Authors: M E DeBortoli, H Abou-Issa, B E Haley, Y S Cho-Chung
• Journal: Biochemical and biophysical research communications (Biochem Biophys Res Commun) Vol. 127 Issue 2 Pg. 699-706 (Mar 15 1985) ISSN: 0006-291X [Print] United States
• PMID: 3884015 (Publication Type: Journal Article)

Chemical References

• Neoplasm Proteins
• Receptors, Estrogen
• Receptors, Progesterone
• Collodion
• HRAS protein, human
• Proto-Oncogene Proteins p21(ras)

Topics

• Animals
• Breast Neoplasms (metabolism)
• Collodion
• Electrophoresis, Polyacrylamide Gel
• Female
• Humans
• Immunochemistry
• Mammary Neoplasms, Experimental (metabolism)
• Neoplasm Proteins (biosynthesis)
• Neoplasms, Hormone-Dependent (metabolism)
• Oncogenes
• Proto-Oncogene Proteins p21(ras)
• Rats
• Rats, Inbred Strains
• Receptors, Estrogen (analysis)
• Receptors, Progesterone (analysis)