Strong ALK and PD-L1 positive IHC expression related ALK amplification in an advanced lung sarcomatoid carcinoma: A therapeutic trap?

Objectives Immunohistochemistry (IHC) is considered as a screening method for ALK rearrangement thanks to its excellent sensitivity. Strong marking on immunohistochemistry give the go-ahead start tyrosine kinase inhibitors (ALK TKI). Lack of therapeutic response may then lead suspicion molecular alterations other than rearrangements. Methods We present patient with strong and PD-L1 positive IHC expression lung sarcomatoid carcinoma initial life-threatening disease progression after beginning TKI. also review literature summarize amplification clinical features management in cancers. Results Fluorescence situ Hybridization (FISH) revealed anatomopathological samples. led initiation immune checkpoint inhibitor (ICI) second line treatment, an response. Conclusion demonstrated that test, these cases, must be interpreted caution. FISH analysis has recommended confirm results case unusual phenotype, such smoker or cancer adenocarcinoma. Although seems not sensitive ICI, further investigations should conducted types alterations. amplifications, observed case, impediment taking into account treatment by immunotherapy.