Is it possible to become a Bone Marrow donor for people who have cancer?

Having researched the matter, we have learned that there are alternatives to bone marrow donation from donors. There are new medical techniques available that use either the very same patient’s marrow or his blood to assist in the production of new marrow. With this new procedure, there seems to be no need to use the marrow of another person. Therefore, it will not be permissible to donate one’s bone marrow to another patient. However, if it is not possible or it will cause harm to the individual if he uses his own blood or marrow and a reliable experienced doctor advises that another person’s blood be used for the same procedure, then it will be permissible to use the donated blood for the procedure.

(Fatāwā Mahmūdiyah, vol. 18, pg. 328, Farūqiyah)

(Fatāwā Rahīmiyah, vol. 10, pg. 175, Dar al-Ishat)

And Allah knows best