How are malignant tumors different from benign tumors? Why are some patients treated with $\alpha$-interferons? [2 marks]

Benign tumors are confined to their original location and do not spread to other parts of the body whereas malignant tumors grow very rapidly while damaging the normal cells surrounding it. [1 mark]

Tumor cells are able to avoid detection and destruction by the immune system. $\alpha$-interferons (biological response modifiers) activate the immune system and help in destroying tumors. Hence this is a method of treatment for patients with tumors. [1 mark]