Mutation in the epidermal growth factor receptor (EGFR) is observed in about 10% of patients diagnosed with non-small cell lung cancer (NSCLC) in the United States and 35% in Asia

Mutation in the epidermal growth factor receptor (EGFR) is observed in about 10% of patients diagnosed with non-small cell lung cancer (NSCLC) in the United States and 35% in Asia. EGFR belongs to a family of receptor tyrosine kinases that phosphorylate their substrates upon activation, which leads to cancer cell survival and proliferation. Tyrosine kinase inhibitors, such as gefitinib and erlotinib, have been successful in treating patients with NSCLC. A type of mutation that is commonly found in EGF receptor gene is deletion in exon 19

a. Based on what you know about gene mutation, hypothesize how the deletion in exon 19 can lead to a gain of function mutation rather than a loss of function mutation. (3 points)

b. Another type of mutation commonly found in EGFR is L858R amino acid substitution How severe is the effect of this mutation on EGFR function? Explain your answer. (2 points)