A novel HIP1-ALK fusion variant in lung adenocarcinoma showing resistance to Crizotinib

Abstract

Anaplastic lymphoma kinase (ALK) rearrangements have been identified in 3–5 % non-small cell lung cancer (NSCLC) patients, with echinoderm microtubule associated protein like 4 gene (EML4) being the most common fusion partner. Huntingtin-interacting protein 1 (HIP1) has been recently identified as a novel fusion partner fused to ALK in NSCLC with three different HIP1-ALK variants reported (H28:A20), (H21:A20) and (H30:A20) to date [1Fang D.D. Zhang B. Gu Q. Lira M. Xu Q. Sun H. Qian M. Sheng W. Ozeck M. Wang Z. Zhang C. Chen X. Chen K.X. Li J. Chen S.H. Christensen J. Mao M. Chan C.C. HIP1-ALK, a novel ALK fusion variant that responds to crizotinib.J. Thorac. Oncol. 2014; 9: 285-294Abstract Full Text Full Text PDF PubMed Scopus (69) Google Scholar, 2Hong M. Kim R.N. Song J.Y. Choi S.J. Oh E. Lira M.E. Mao M. Takeuchi K. Han J. Kim J. Choi Y.L. HIP1-ALK, a novel fusion protein identified in lung adenocarcinoma.J. Thorac. Oncol. 2014; 9: 419-422Abstract Full Text Full Text PDF PubMed Scopus (49) Google Scholar, 3Ou S.H. Klempner S.J. Greenbowe J.R. Azada M. Schrock A.B. Ali S.M. Ross J.S. Stephens P.J. Miller V.A. Identification of a novel HIP1-ALK fusion variant in Non-Small-Cell Lung Cancer (NSCLC) and discovery of ALK I1171 (I1171N/S) mutations in two ALK-rearranged NSCLC patients with resistance to Alectinib.J. Thorac. Oncol. 2014; 9: 1821-1825Abstract Full Text Full Text PDF PubMed Scopus (75) Google Scholar]. Analogous to the well-known multiple variants of EML4-ALK, it is likely that other HIP1-ALK fusion variants also exist in NSCLC [[3]Ou S.H. Klempner S.J. Greenbowe J.R. Azada M. Schrock A.B. Ali S.M. Ross J.S. Stephens P.J. Miller V.A. Identification of a novel HIP1-ALK fusion variant in Non-Small-Cell Lung Cancer (NSCLC) and discovery of ALK I1171 (I1171N/S) mutations in two ALK-rearranged NSCLC patients with resistance to Alectinib.J. Thorac. Oncol. 2014; 9: 1821-1825Abstract Full Text Full Text PDF PubMed Scopus (75) Google Scholar]. Herein, we report a novel HIP1-ALK fusion variant (H19:A20) in a patient with lung adenocarcinoma. Contrary to the previous reports that patients harboring HIP1-ALK responded well to Crizotinib, the present case displayed primary clinical resistance to Crizotinib. A 56-year-old Chinese women without smoking history was referred to our hospital for waist pain in November 2019. Computed tomography (CT) showed bone destruction and soft tissue mass close to the left pedicle of fourth lumbar vertebra. Further positron emission tomography–computed tomography (PET-CT) revealed multiple bone destruction (right 6th anterior rib, 7th cervical vertebra, 1 st/4th lumbar vertebra), multiple lymph node enlargement (including the right hilum, right mediastinal trachea, left upper mediastinum, left clavicle area, right internal mammary artery, right axillary) and multiple nodules in the lower lobe of both lungs (Fig. 1A). No brain metastasis was detected. Palliative metastasectomy of the lumbar spine was performed on November 19, 2019 and postoperative pathological examination revealed atypia cells in the fibrocartilage tissue. Immunohistochemistry (IHC) analysis indicated positive expression for Napsin A, TTF-1, CK7 and ALK, suggesting a primary lung adenocarcinoma (Fig. 1B). Subsequently, next-generation sequencing (NGS) analysis based on a 168-gene panel (Burning Rock Biotech, Guangzhou, China) was performed on tissue specimens, which revealed a novel HIP1-ALK (H19:A20, with an abundance of 1.67 %). The fusion gene retained the entire ALK tyrosine kinase domain (Fig. 2) and co-mutation was not detected. The patient was administered with Crizotinib (250 mg, twice a day) as first-line therapy since November 2019. She complained a progressive dyspnea and unbearable bone pain 2 months later. A subsequent chest CT scan displayed massive pleural effusion in the lower lobe of the right lung, indicating a disease progression during Crizotinib treatment. Pleural effusion was drained and a second NGS analysis based on a 520-gene panel was performed aiming to explore the resistance mechanism. Again, HIP1-ALK (H19:A20, with an abundance of 6.23 %) was detected, yet neither point-mutation in kinase domain nor alternative pathway activation was revealed. The patient was then administered with Alectinib (600 mg, twice a day) in January 2020. Follow-up CT scans showed continuously decreased pleural effusion and reduced target nodules in the lower lobe of both lungs. The progression-free survival (PFS) has exceeded 9 months till now (Fig. 1C).Fig. 2Identification of a novel HIP1-ALK fusion variant in a NSCLC patient. (A) Sequencing reads of ALK and HIP1 were visualized by the Integrative Genomics Viewer (IGV). (B) A schematic map showing the structure of the HIP1- ALK fusion locus. Exons 1–19 of HIP1 (blue) were fused to exons 20–29 of ALK (yellow) through intron19 of HIP1 and intron19 of ALK.View Large Image Figure ViewerDownload Hi-res image Download (PPT) Fang et al. [[1]Fang D.D. Zhang B. Gu Q. Lira M. Xu Q. Sun H. Qian M. Sheng W. Ozeck M. Wang Z. Zhang C. Chen X. Chen K.X. Li J. Chen S.H. Christensen J. Mao M. Chan C.C. HIP1-ALK, a novel ALK fusion variant that responds to crizotinib.J. Thorac. Oncol. 2014; 9: 285-294Abstract Full Text Full Text PDF PubMed Scopus (69) Google Scholar] has demonstrated that HIP1-ALK (H28; A20) was sensitive to treatment with Crizotinib in vitro, Hong et al. [[2]Hong M. Kim R.N. Song J.Y. Choi S.J. Oh E. Lira M.E. Mao M. Takeuchi K. Han J. Kim J. Choi Y.L. HIP1-ALK, a novel fusion protein identified in lung adenocarcinoma.J. Thorac. Oncol. 2014; 9: 419-422Abstract Full Text Full Text PDF PubMed Scopus (49) Google Scholar] showed that HIP1-ALK (H21; A20) responded well to Crizotinib with no recurrence or metastasis during the 15 months of follow-up, and Ou et al. [[3]Ou S.H. Klempner S.J. Greenbowe J.R. Azada M. Schrock A.B. Ali S.M. Ross J.S. Stephens P.J. Miller V.A. Identification of a novel HIP1-ALK fusion variant in Non-Small-Cell Lung Cancer (NSCLC) and discovery of ALK I1171 (I1171N/S) mutations in two ALK-rearranged NSCLC patients with resistance to Alectinib.J. Thorac. Oncol. 2014; 9: 1821-1825Abstract Full Text Full Text PDF PubMed Scopus (75) Google Scholar] described that HIP1-ALK (H30:A20) showed response to multiple ALK inhibitors including Crizotinib. We report another novel breakpoint variant (H19:A20) of HIP1-ALK, whose response to Crizotinib has not been previously identified. In this case, the patient harboring HIP1-ALK (H19:A20) showed resistance to Crizotinib with progression of pleural effusion and aggravation of clinical symptoms, indicating that HIP1-ALK is a heterogeneous molecular group and different breakpoint variants of HIP1–ALK may lead to different clinical responses to Crizotinib. Heterogeneity of clinical responses exist not only in the different ALK fusion partners but also in the different breakpoint variants. Typically, the efficacy of Crizotinib in patients with ALK-EML4 differed, according to different types of variants. Yoshida et al. reported that patients with ALK variant 1 had a significantly longer PFS to Crizotinib than patients with non–variant 1 [[4]Yoshida T. Oya Y. Tanaka K. Shimizu J. Horio Y. Kuroda H. Sakao Y. Hida T. Yatabe Y. Differential crizotinib response duration among ALK fusion variants in ALK-Positive non-small-cell lung cancer.J. Clin. Oncol. 2016; 34: 3383-3389Crossref PubMed Scopus (189) Google Scholar]. The proposed explanation by Heuckmann was that the various parts of EML4 fused to ALK affected the protein stability, inhibitor-induced protein degradation, and drug sensitivity [[5]Heuckmann J.M. Balke-Want H. Malchers F. Peifer M. Sos M.L. Koker M. Meder L. Lovly C.M. Heukamp L.C. Pao W. Kuppers R. Thomas R.K. Differential protein stability and ALK inhibitor sensitivity of EML4-ALK fusion variants.Clin. Cancer Res. 2012; 18: 4682-4690Crossref PubMed Scopus (205) Google Scholar]. The specific mechanism still needs further investigation, and remains to be explored. NGS displays a significant capability to detect fluorescence in situ hybridisation (FISH)-negative, FISH-unusual and novel fusion type ALK-rearranged NSCLC. Currently, more than 90 ALK fusion partners have been discovered. Large-scale clinical data relevant to the efficacy of ALK-TKIs in lung cancer harboring these rare ALK fusions are not fully available. Clinicians around the world are encouraged to report these novel fusions with information on the fusion breakpoints, responses to ALK tyrosine kinase inhibitors (TKIs) and NGS may be used as a routine method. Reports on such incidents will provide better understanding of ALK-TKIs applications in the rare ALK rearrangements and provide a reference for future clinical treatment.