Open AccessTwo Cases of ALK-Altered Cancers of Unknown Primary Diagnosed by Immunohistochemistry
Author(s) -
Kato Yoriko,
Shimazu Kazuhiro,
Fukuda Koji,
Yoshida Taichi,
Taguchi Daiki,
Shinozaki Hanae,
Nanjyo Hiroshi,
Shibata Hiroyuki
Publication year - 2022
Publication title -
case reports in oncology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.365
H-Index - 19
ISSN - 1662-6575
DOI - 10.1159/000521157
Subject(s) - case report
Cancer of unknown primary (CUP) accounts for 5% of all malignancies. Patients with CUP may live averagely for 8 months after diagnosis, and thus, rapid and reasonable diagnosis is necessary. Among patients with CUP, anaplastic lymphoma kinase (ALK)-overexpressing CUPs, whose primary sites were confirmed to be the lungs (Lung-CUP) by using antibodies against cytokeratin 7, thyroid transcription factor-1, and Napsin A, along with clinical characteristics progressed rapidly and were very sensitive to the ALK inhibitor alectinib. The incidence of ALK alteration in Lung-CUP is 19%. Consequently, it is advised that Lung-CUP be examined by immunohistochemistry (IHC) with an anti-ALK antibody. Alternative examinations, such as a cancer genome test, require as much as 2 months to complete, whereas IHC can be completed within days. In this report, a rapid assessment by IHC led to alectinib treatment, which resulted in good outcomes in 2 cases of Lung-CUP. Alectinib was effective for ALK-altered Lung-CUPs.