18
IASLC ATLAS OF ALK TESTING IN LUNG CANCER
Preanalytic Requirements
As a DNA-based assay, FISH has an important advantage in its robustness. However, the assay is affected by many factors, especially time to fixation, time of fixation, and type of fixative, all of which can lead to DNA degradation (Table 1) (Hunt 2007, Babic 2010). For example, long cold ischemia, or more than 1 hour from the time the tissue is excised when it is placed in fixation, may result in DNA degradation and failure of FISH testing (Khoury 2012). The ideal fixation time is considered to be between 6 and 48 hours (Hunt 2007, Babic 2010); both shorter and longer fixation times may influence test performance significantly.
Table 1. Preanalytic R X??[Y[?][?????X??\??[?T???\?[Y]\??[YH ??^][??^]]?H[YH??^][? ?\\?][??X?[Y[? ??Y?H??Y?H [YH?????????Y?H??][???????????Y?H [YH???] ?X?[??X?[?Y?X?][????X??[Y[?][??\? ??\? ???X?K??^?YY[?? H ? L H?]] ?[?Y??\?Y??X[[?
?M ?\?Y??[?Y[X?YY ?X?[???]]H X??\???
H0?LH3?H\??YH?????
YX[
H?? ?[]?[?Y?[? ??\???][?? ??X?Y???HY? X] [? [ZY] H
M? ?YZ??
YX[
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
K?? [\\?] \?K^ ??\?H ?Y? X] [ZY] JK[?X]\?X[ ? ?X??X?Y ??HY?Y[????][??X^H?Z[ ? X??Y^?K?H?[Y\??\? ?\?XX?\??Y??H[?Y?\? X??Y^?][??[?[ ??Y??X? \?[??H ?Z X??Y^?][? ???Y \?H[?? Y\?H ?\?Y\?? ?\ ? ??X?[]]H ??H [?] ?][?[?? H?X?]\?? H [[??[ ?\??YH \?YXX?[^?][?\?X?Y]?Y?HY?\?[??\??H ??Z[? ? ?X? \?\??]??[ ?X?[Y[?? ?\??Y[?X?[ H ?H?]?[? ????? ? [[?? ?] ??Y??\?[?X][?\?H[?H ?[??]]?H ? ?Z X??Y^?][? ???Y \?\? ?\?X\??X???X?[?]X?[??\? [[??\?H[?H ?\?\?[? ??? Z X??Y^?][? ?\?\?]\?[??Y\]X]H[[Z[?][?? [???[? ??H ?]?]X?X\?[?? ?Y?[[?[??] K?X[?H[ \??]]?H ????? ?X^H?[?\?]H^?[[? ?\?[ ?? \?X??]?Y\?X^B??