Elevated expression of the tumor suppressing protein p53 is associated with the presence of mouse mammary tumor-like env gene sequences (MMTV-like) in human breast cancer.
In a previous study, we had detected the presence of mouse mammary tumor virus (MMTV)-like envelope (ENV) gene sequences in both the breast tumors and non-Hodgkin's lymphoma tissue of two of our breast tumor patients who had been diagnosed simultaneously with both malignancies.
Human breast tumors contain DNA sequences with high homology to the Mouse Mammary Tumor Virus (MMTV) env gene. env encodes the membrane glycoprotein that binds to the MMTV receptor (Mtvr) in mouse tissues and is required for infection.
Using similar PCR procedures and stringent hybridization techniques, we have detected the presence of MMTV-like ENV gene sequences in 37% of the human breast tumors that we have analyzed.