role of HPV(human papilloma virus) in breast carcinogenesis studied
 

I had seen a paper saying the two were not related, then came across this abstract showing a complicated (indirect) relationship--food for thought?

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Human papillomavirus type 16 transform
non-invasive breast cancer cells to invasive cells
Yasmeen A, Kandouz M, Bismar T, Foulkes W,
Mousavi G, Benezra R, Desprez P-Y, Al Moustafa A.
McGill University, Montreal, QC, Canada; Memorial
Sloan-Kettering Cancer Center, New York, NY;
California Pacific Medical Center Research Institute,
San Francisco, CA
Breast Cancer is characterized by a marked propensity
for invasion and spreading through the lymphatic sys-
tem, with distant metastases developing in 50–60% of
cases. Human papillomaviruses (HPVs) could be
important risk factors for breast carcinogenesis and
metastasis, as roughly 52% of breast cancers are posi-
tive for high-risk HPVs. However, how these viruses
enhance susceptibility to breast cancer is not clear. To
determine the role of high-risk HPVs in human breast
carcinogenesis, we examined the effect of E6/E7 of
HPV type 16 in two non-invasive breast cancer cell
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lines, MCF7 and BT20. We report that E6/E7 induce
cell invasion and metastasis abilities of MCF7 and
BT20 in vitro and in vivo, respectively, in comparison
with the wild type cells. In parallel, we found that HPV
type 16 is present in invasive and metastatic breast
cancer as opposed to in-situ breast cancer and normal
mammary epithelial tissue. We found that E6/E7 up
regulate the expression of Id.1, a family member of
HLH transcription factors, in MCF7 and BT20 cell
lines. To confirm the role of Id-1 in cell invasion and
metastasis induced by E6/E7 in mouse normal embry-
onic fibroblast (NEF), wild type (wt), and knockout Id-
1 (Id-1[sup–/–) cells. We found that E6/E7 provoke
cell invasion and metastasis of NEF-wt but not
Id-1[sup–/– cells in vitro and in vivo. Our data suggest
that HPV infections play an important role in the
development of human breast metastases cancers
through ID-1 regulation.

Thanks Lani. I don't fully understand, but I would not be surprised at all if viruses were involved. BB