'She is my breast cancer sister'
12 February 2014 Last updated at 00:12 GMT
Palestinian housewife Ibtisam Erekat and Israeli Orthodox Jew Ruth Ebenstein share an unusual relationship.
The two women met three years ago through the Cope forum, a support group for breast-cancer sufferers and survivors that draws in both Israelis and Palestinians.
Their friendship has evolved and grown through their experiences since then.
The two women spoke to BBC News about why they now call each other sister.