Here's an interesting study
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3063649/
which showed that Andrographolide, an herbal medicine, inhibits Interleukin-6 expression and suppresses prostate cancer cell growth.
Now prostate cancer isn't breast cancer, BUT........
it is interesting! I have no idea what Andographolide is but I will research it and see what I find out.
Wow! Look at this one!
http://www.pnas.org/content/105/38/14692.full
This shows that EGCG, epigallocatechin-3-gallate (EGCG) inhibits IL-6 synthesis. I find this particularly interesting because I have been on EGCG (green tea extract) for about 3-4 months. Fascinating!