Chapter 1
Candidates for ALK Testing
By Fred R. Hirsch, Elisabeth Brambilla, and Ming Sound Tsao
It is widely recognized that the detection of ALK gene rearrangements is important for selecting effective therapy for patients with advanced NSCLC. However, it is unclear whether clinicopathologic features may help in determining which patients should have ALK testing. Rearrangements of the ALK gene are more often found in lung tumors from never-smokers, light ex-smokers, and younger patients and in tumors classified as adenocarcinoma. But is it plausible to exclude older and smoking patients with squamous histology from NSCLC-Others ALK testing? In published studies, about 70% (n=376) ADSC (n=78) to 80% of patients with ALK-positive NSCLC have been never-smokers (compared with SCC 20% to 30% of previous or current smokers), (n=1411) NSCLC and have been younger (40 to 50 years old) (n=4025) than people with NSCLC overall (60 to 70 years old) or people with NSCLC with EGFR ADC mutation (60 to 65 years old) (Rodig 2009, (n=6775) Shaw 2009, Bang 2010, Kwak 2010, Shaw 2011). However, in all studies, tumors harboring ALK rearrangement have also been found 11.1 in patients older than 70 years or younger 9 than 40 years. 5.7 5.2 4.8 According to these data, it is not clear that smoking history and age should pre1.3 clude ALK testing in any patient. Histology NSCLC ADC ADC SCC ADSC NSCLCOthers (unselected) (selected) appears to be a more important selection criterion; among more than 12,000 lung Figure 1. Summary of studies on ALK gene rearrangement in cancer specimens that have been reported NSCLC. A. Number of NSCLC cases that have been studied for ALK aberration and reported in ?????????????????5???????????????????????1,?????????????????q9M
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