Exposure to Bovine Leukemia Virus Is Associated with Breast Cancer: A Case-Control Study

Area of Science:

• Oncology
• Virology
• Epidemiology

Background:

• Known breast cancer risk factors include age, hormones, genetics, and lifestyle, but the initiating agents remain unclear.
• Bovine leukemia virus (BLV), an oncogenic cattle virus, has been previously detected in human breast epithelium.
• The study investigates the association between BLV DNA presence in human mammary epithelium and breast cancer.

Purpose of the Study:

• To determine if BLV DNA in human mammary epithelium is associated with breast cancer.
• To quantify the association between BLV DNA and breast cancer risk.

Main Methods:

• A case-control study utilized archival breast tissues from 239 donors.
• Breast cancer cases were compared to normal controls using medical records and pathological examination.
• In situ-PCR detected BLV DNA in mammary epithelium to assess breast exposure to BLV.

Main Results:

• BLV DNA was found in 59% of breast cancer cases versus 29% of normal controls.
• The adjusted odds ratio for breast cancer associated with BLV DNA was 3.07 (p = .0004).
• An intermediate frequency of BLV DNA (38%) was observed in premalignant breast changes.

Conclusions:

• Amplified BLV DNA in breast tissue is significantly associated with breast cancer.
• The observed odds ratio is comparable to established risk factors like reproductive history and hormones.
• Findings suggest potential for primary and secondary breast cancer prevention strategies.
• BLV DNA presence in breast tissue is a significant risk factor for breast cancer.