Immunostaining of cancer cells

A breast tumour (right) whose signals to nearby connective tissue have been blocked has more cells with oestrogen receptors (brown) than a tumour (left) that can communicate freely with its neighbours. Credit: P. Roswell et al./Nat. Med.

Cancer

Communications breakdown puts resistant cancer at risk

Cell-signalling blockade makes breast tumours vulnerable to drug treatment.

An aggressive form of breast cancer can be transformed into a more-easily treated one by disrupting tumours’ contact with their environment.

Some 10–15% of breast-cancer tumours lack receptors for the hormones oestrogen and progesterone. These tumours do not respond to hormone-blocking drugs such as tamoxifen, and patients tend to have a poor prognosis.

Kristian Pietras at Lund University in Sweden and his colleagues used either drugs or gene editing to block the chemical signals that these tumours send to cells in surrounding connective tissue. After this communication was obstructed, the tumours made oestrogen receptors.

When mice with the altered tumours received hormone-blocking therapy, tumour growth slowed drastically, whereas unaltered tumours maintained rapid growth. The results show that it may be possible to treat cancer by targeting the environment surrounding tumours, as well as the tumours themselves, the authors say.