I can't understand the difference.

Could you explain what the difference is between negative and positive breast cancer please?

[Fiercefighter13]

Hi there, my understanding of how things work is that cancer cells have receptor sites that it uses to help "feed" or get energy from and help the cells continue to divide and stay alive. ER and or PR positive cells use estrogen and or progesterone to keep them going and dividing...in other words they are feeding off of one or both of those hormones to keep going. Her2 positive cells can be ER/PR positive as well or not at all. These cells have a genetic mutation that allows them to use Her2 protein to replicate. Cells that are triple negative, do not use estrogen, progesterone or Her2 protein to feed or replicate so they feed on what I would guess normal cells feed on. Many of the treatments currently focus on the cell's receptor site so ER/PR positive cancers try to reduce estrogen eliminating the ability of those cells to feed and replicate....I don't think anything on the market targets progesterone. Her2 positive cancer treatment target that site by eliminating it's ability to use Her2 protein to feed and replicate. I believe triple negative cancers are targeted by agents that seek out and destroy the cells themselves either by messing with it's replication dna or feeding. This is my version and I am not a medical professional, but it's my take away after doing a lot of research and reading.