Identification of CARS-ALK fusion in primary and metastatic lesions of an inflammatory myofibroblastic tumor

Establishment and characterization of TK-ALCL1: a novel NPM-ALK-positive anaplastic large-cell lymphoma cell line

TK-ALCL1, a novel anaplastic lymphoma kinase (ALK)-positive anaplastic large-cell lymphoma (ALK+ ALCL) cell line, was established from the primary tumor site of a 59-year-old Japanese male patient. The immune profile of TK-ALCL1 corresponds to that seen typically in primary ALCL cells, i.e., positive for ALK, CD30, EMA, and CD4, but negative for CD2, CD3, CD5, CD8a, and EBV-related antigens. The rearrangement of the T cell receptor-gamma locus shows that TK-ALCL1 is clonally derived from T-lineage lymphoid cells. FISH and RT-PCR analysis revealed that TK-ALCL1 has the nucleophosmin (NPM)-ALK fusion transcript, which is typical for ALK+ ALCL cell lines. When TK-ALCL1 was subcutaneously inoculated into 6-week-old BALB/c Rag2-/-/Jak3-/- (BRJ) mice, it formed tumor masses within 4-6 weeks. Morphological, immunohistochemical, and molecular genetic investigations confirmed that the xenograft and the original ALCL tumor were identical. The ALK inhibitors Alectinib and Lorlatinib suppressed proliferation in a dose-dependent manner. Thus, TK-ALCL1 provides a useful in vitro and in vivo model for investigation of the biology of ALK+ ALCL and of novel therapeutic approaches targeting ALK.

Individualized targeted treatment in a case of a rare TFG::ROS1 fusion positive inflammatory myofibroblastic tumor (IMT)

BACKGROUND

Inflammatory myofibroblastic tumor (IMTs) are rare mesenchymal neoplasms with slow growth. Resection is considered as therapeutic standard, with chemotherapy being insufficiently effective in advanced disease. ALK translocations are present in 50% of cases, ROS1 fusions (YWHAE::ROS1, TFG::ROS1) are extremely rare. Here, we present a case with TFG::ROS1 fusion and highlight the significance of molecular tumor boards (MTBs) in clinical precision oncology for post-last-line therapy.

CASE PRESENTATION

A 32-year-old woman presented with IMT diagnosed at age 27 for biopsy and treatment evaluation. Previous treatments included multiple resections and systemic therapy with vinblastine, cyclophosphamide, and methotrexate. A computed tomography scan showed extensive tumor infiltration of the psoas muscles and the posterior abdomen. Next generation sequencing revealed an actionable ROS1 fusion (TFG::ROS1) with breakpoints at exon 4/35 including the kinase domain and activating the RAS-pathway. TFG, the Trk-fused gene, exerts functions such as intracellular trafficking and exhibits high sequence homology between species. Based on single reports about efficacy of ROS1-targeting in ROS1 translocation positive IMTs the patient was started on crizotinib, an ATP-competitive small molecule c-MET, ALK and ROS1-inhibitor. With a follow-up of more than 9 months, the patient continues to show a profound response with major tumor regression, improved quality of life and no evidence for severe adverse events.

CONCLUSION

This case underscores the importance of the availability of modern molecular diagnostics and interdisciplinarity in precision oncology to identify rare, disease-defining genotypes that make an otherwise difficult-to-treat disease targetable.

Inflammatory myofibroblastic tumor of the distal common bile duct: Literature review with focus on pathological examination

Inflammatory myofibroblastic tumor (IMT) of the biliary tract is rare, and often difficult to diagnose or to distinguish from other tumors due to its atypical clinical presentation and nonspecific radiological features. Histologically, IMTs are (myo)fibroblastic neoplasms with a prominent inflammatory infiltrate. They are characterized by receptor tyrosine kinase gene rearrangements, most often involving an anaplastic lymphoma kinase (ALK) translocation. The final diagnosis of IMT depends on histopathology and immunohistochemical examination. In this manuscript, we provide a clinical and morphomolecular overview of IMT and the difficulties that may arise in using immunohistochemical and molecular techniques in diagnosing IMT.

Azaindole derivatives as potential kinase inhibitors and their SARs elucidation

Currently, heterocycles have occupied an important position in the fields of drug design. Among them, azaindole moiety is regarded as one privileged scaffold to develop therapeutic agents. Since two nitrogen atoms of azaindole increase the possibility to form hydrogen bonds in the adenosine triphosphate (ATP)-binding site, azaindole derivatives are important sources of kinase inhibitors. Moreover, some of them have been on the market or in clinical trials for the treatment of some kinase-related diseases (e.g., vemurafenib, pexidartinib, decernotinib). In this review, we focused on the recent development of azaindole derivatives as potential kinase inhibitors based on kinase targets, such as adaptor-associated kinase 1 (AAK1), anaplastic lymphoma kinase (ALK), AXL, cell division cycle 7 (Cdc7), cyclin-dependent kinases (CDKs), dual-specificity tyrosine (Y)-phosphorylation regulated kinase 1A (DYRK1A), fibroblast growth factor receptor 4 (FGFR4), phosphatidylinositol 3-kinase (PI3K) and proviral insertion site in moloney murine leukemia virus (PIM) kinases. Meanwhile, the structure-activity relationships (SARs) of most azaindole derivatives were also elucidated. In addition, the binding modes of some azaindoles complexed with kinases were also investigated during the SARs elucidation. This review may offer an insight for medicinal chemists to rationally design more potent kinase inhibitors bearing the azaindole scaffold.

Discovery of imidazo[1,2-b]pyridazine macrocyclic derivatives as novel ALK inhibitors capable of combating multiple resistant mutants

Anaplastic lymphoma kinase (ALK)-tyrosine kinase inhibitor (TKI) often loses effectiveness against non-small cell lung malignancies (NSCLCs) with ALK gene rearrangements (ALK⁺). 19 novel imidazo[1,2-b]pyridazine macrocyclic derivatives were designed, synthesized, and tested for their biological activities in an effort to develop ALK inhibitors that would overcome second-generation ALK-TKIs, particularly the G1202R mutation and the lorlatinib-resistant L1196M/G1202R double mutations. Of all the target substances, O-10 had the most effective enzymatic inhibitory activity, with IC₅₀ values for ALK^WT, ALK^G1202R, and ALK^{L1196M/G1202R} of 2.6, 6.4, and 23 nM, respectively. O-10, on the other hand, reduced the growth of ALK-positive Karpas299, BaF3-EML4-ALK^G1202R, and BaF3-EML4-ALK^{L1196M/G1202R} cells with IC₅₀ values of 38, 52, and 64 nM, respectively. This was equally effective to the reference drug Repotrectinib (IC₅₀ = 40, 164, and 208 nM). The kinase selectivity profile, liver microsome stability test and in vivo pharmacokinetic properties in SD rats of compound O-10 were further evaluated. O-10 was regarded as an effective ALK inhibitor for the treatment of mutations overall.

Epithelioid Fibrous Histiocytoma with CARS-ALK Fusion: First Case Report

Epithelioid fibrous histiocytoma (EFH) is a type of uncommon skin tumor mostly harboring Anaplastic Lymphoma Kinase (ALK) gene rearrangement, with different fusion partners reported. Whether this tumor is a separate entity or has a relationship with conventional fibrous histiocytomas is still a matter of debate. Benign course is the rule after complete surgical excision. A rare subtype of EFH with fusiform cells has been described, with specific fusion partners. Inflammatory myofibroblastic tumor (IMT) is a type of soft tissue tumor rarer than EFH, and it can display distant metastases. Some cases of primary cutaneous IMT included two with Cysteinyl-tRNA Synthetase 1 (CARS)-ALK rearrangement. IMT can have the same fusion partners as EFH, such as DCTN1, TMP3 or EML4 genes. We report the case of a 42-year-old woman presenting EFH with fusiform morphology harboring CARS-ALK fusion and discuss similarities and differences with IMT.

Hallmarks of Anaplastic Lymphoma Kinase Inhibitors with Its Quick Emergence of Drug Resistance

Anaplastic lymphoma kinase (ALK) is one of the most popular targets for anticancer therapies. In the past decade, the use of anaplastic lymphoma tyrosine kinase inhibitors (ALK-TKIs), including crizotinib and ceritinib, has been a reliable and standard options for patients with lung cancer, particularly for patients with nonsmall cell lung carcinoma. ALK-targeted therapies initially benefit the patients, yet, resistance eventually occurs. Therefore, resistance mechanisms of ALK-TKIs and the solutions have become a formidable challenge in the development of ALK inhibitors. In this review, based on the knowledge of reported ALK inhibitors, we illustrated the crystal structures of ALK, summarized the resistance mechanisms of ALK-targeted drugs, and proposed potential therapeutic strategies to prevent or overcome the resistance.

Locally Advanced Inflammatory Myofibroblastic Tumor Treated With Targeted Therapy: A Case Report and Literature Review

Inflammatory myofibroblastic tumors (IMTs) are known to be associated with anaplastic lymphoma kinase (ALK) gene rearrangements. Other molecular alterations such as ROS proto-oncogene 1, receptor tyrosine kinase (ROS1), neurotrophic tyrosine receptor kinase (NTRK), and platelet-derived growth factor receptor (PDGFR) have also been identified in IMTs. Although there are no randomized controlled clinical trials comparing chemotherapy, tyrosine kinase inhibitors (TKIs), or other systemic therapies, the literature demonstrates the use of ALK-targeted TKIs as an effective strategy for the treatment of locally advanced or metastatic ALK-rearranged IMTs. This case report describes a patient with an ALK-rearranged locally advanced pulmonary IMT who was treated with neoadjuvant-intent crizotinib. The patient had a very favorable response to therapy, and surgery was declined. It is difficult to determine the duration and sequencing of TKI use in these settings as there is little published data to guide decisions. This report also includes a comprehensive compilation of published IMT cases with molecular alterations treated with systemic therapy, which also highlighted the duration of therapies and clinical outcomes.

Cutaneous Inflammatory Myofibroblastic Tumor with CARS-ALK Fusion: Case Report and Literature Review

Cutaneous inflammatory myofibroblastic tumors (IMT) constitute a rare entity, generating a diagnostic pitfall when diagnosing spindle cell proliferation within the dermis. Raising awareness of this tumor among dermatopathologists remains vital in differentiating it from common cutaneous tumors such as fibrous histiocytoma, atypical fibroxanthoma, melanoma, poorly differentiated carcinoma, and other more aggressive tumors. Accurate diagnosis of IMT aid in ensuring appropriate management and follow-up for patients while preventing unnecessary harm and overtreatment. Here we report a case of a 38-year-old female with a painless, slow-growing nodule of the left posterior scalp initially diagnosed as a dermatofibroma. The histological examination revealed an ill-defined dermal nodule of spindled cells without connection or infiltration of the epidermis. At high power, the cells were arranged in fascicles with a prominent background of lymphocytic infiltrate. Immunohistochemical analysis showed strong diffuse immunoreactivity for anaplastic lymphoma kinase (ALK), targeted RNA sequencing identified a CARS-ALK fusion ultimately confirming the accurate diagnosis of a cutaneous IMT. This article is protected by copyright. All rights reserved.

Intraocular myofibroblastoma tumour of the ciliary body: a case report and literature review

Background

Inflammatory Myofibroblastoma Tumors (IMTs) are extremely tumour rare in the intraocular.

Case presentation

A ciliary body tumor was found under slit lamp biomicroscopy in a 55-year-old male first diagnosed with cataract. Then this patient underwent trans-sclera resection via partial lamellar sclerouvectomy and par plans vitrectomy to remove the mass. Hematoxylin and eosin (HE) staining and immunohistochemistry findings showed that the characteristics of the tumor were consistent with IMT.

Conclusions

We reported a rare case of intraocular IMT, which is confirmed by H&E staining, and IHC positive staining for Vimentin, Desmin and ALK, while negative staining for SMA, S-100, ki-67, CK, CD68, and calponin.

Functional and pathologic association of aminoacyl-tRNA synthetases with cancer

Although key tumorigenic and tumor-suppressive factors have been unveiled over the last several decades, cancer remains the most life-threatening disease. Multiomic analyses of patient samples and an in-depth understanding of tumorigenic processes have rapidly revealed unexpected pathologic associations of new cellular factors previously overlooked in cancer biology. In this regard, the newly discovered activities of human aminoacyl-tRNA synthases (ARSs) deserve attention not only for their pathological significance in tumorigenesis but also regarding diagnostic and therapeutic implications. ARSs are not only essential enzymes covalently linking substrate amino acids to cognate tRNAs for protein synthesis but also function as regulators of cellular processes by sensing different cellular conditions. With their catalytic role in protein synthesis and their regulatory role in homeostasis, functional alterations or dysregulation of ARSs might be pathologically associated with tumorigenesis. This review focuses on the potential implications of ARS genes and proteins in different aspects of cancer based on various bioinformatic analyses and experimental data. We also review their diverse activities involving extracellular secretion, protein–protein interactions, and amino acid sensing, which are related to cancers. The newly discovered cancer-related activities of ARSs are expected to provide new opportunities for detecting, preventing and curing cancers.

Enzymes called aminoacyl-tRNA synthetases (ARSs), which play a central role in all life, are becoming implicated in several aspects of cancer in ways that may lead to new approaches for prevention, detection and treatment. ARS enzymes catalyse the ligation of amino acids to transfer RNA molecules to allow amino acids to combine in the correct sequences to form proteins. Jung Min Han, Sunghoon Kim and colleagues at Yonsei University, Incheon, South Korea, review researches implicating ARS enzymes and the genes that code for them in a variety of cancers. The behavior of ARS enzymes and their genes are found to be altered in several types of cancer cells in ways that may either initiate or support the onset and development of the disease, through which they could be suggested as targets for novel anti-cancer drugs.

Case Report: Early Distant Metastatic Inflammatory Myofibroblastic Tumor Harboring EML4-ALK Fusion Gene: Study of Two Typical Cases and Review of Literature

Inflammatory myofibroblastic tumor (IMT) is a distinctive neoplasm that frequently arises in the lung and accounts for ~1% of lung tumors. Distant metastatic IMT is extremely rare and has been poorly investigated. This analysis was specifically performed to explore the clinicopathological and genetic features of early distant metastatic IMT. Two typical patients with distant metastatic IMTs were selected, which accounted for 1.13% of all diagnosed IMTs in the last 5 years. One patient was a 55 year-old male, and the other patient was a 56 year-old female. Both primary tumors arose from the lung, and the initial clinical symptoms of the two patients involved coughing. Both of the imaging examinations showed low-density nodular shadows in the lungs with enhancement around the mass. Microscopically, dense arranged tumor cells, prominent cellular atypia, and high mitotic activity with atypical form were more prominent in the metastatic lesions than in the primary lesions. All of the primary and metastatic tumors in both cases showed positive anaplastic lymphoma kinase (ALK) immunostaining and ALK rearrangement via fluorescence in situ hybridization. The EML4 (exon 6)-ALK (exon 20) fusion variant (v3a/b) was identified by using next-generation sequencing (NGS) and was verified by using reverse transcription polymerase chain reaction (RT-PCR). Furthermore, intronic variants of NOTCH1 and synonymous variants of ARAF were also detected via NGS in one IMT for the first time and were verified in all of the primary and metastatic lesions via PCR. Distant metastasis occurred during a short period of time (1 and 2 months) after the first surgery. One patient presented with multiple metastases to the subcutaneous tissue and bone that responded to ALK inhibitor alectinib therapy, and the tumor was observed to regress 10 months after the initial ALK inhibitor therapy. In contrast, the other patient presented with subcutaneous neck metastasis without ALK inhibitor treatment and succumbed to the disease within 3 months after the surgery. This study demonstrated the possible role of EML4-ALKv3a/b in the malignant progression of IMT and proposed certain therapeutic effects of ALK inhibitors on multiple metastatic IMTs.

Clinicopathologic and Genomic Characterization of Inflammatory Myofibroblastic Tumors of the Head and Neck: Highlighting a Novel Fusion and Potential Diagnostic Pitfall

Inflammatory myofibroblastic tumor (IMT) is a distinctive fibroblastic and myofibroblastic spindle cell neoplasm with an accompanying inflammatory cell infiltrate and frequent receptor tyrosine kinase activation at the molecular level. The tumor may recur and rarely metastasizes. IMT is rare in the head and neck region, and limited information is available about its clinicopathologic and molecular characteristics in these subsites. Therefore, we analyzed a cohort of head and neck IMTs through a multi-institutional approach. Fourteen cases were included in the provisional cohort, but 1 was excluded after molecular analysis prompted reclassification. Patients in the final cohort included 7 males and 6 females, with a mean age of 26.5 years. Tumors were located in the larynx (n=7), oral cavity (n=3), pharynx (n=2), and mastoid (n=1). Histologically, all tumors showed neoplastic spindle cells in storiform to fascicular patterns with associated chronic inflammation, but the morphologic spectrum was wide, as is characteristic of IMT in other sites. An underlying fusion gene event was identified in 92% (n=11/12) of cases and an additional case was ALK-positive by IHC but could not be evaluated molecularly. ALK represented the driver in all but 1 case. Rearrangement of ALK, fused with the TIMP3 gene (n=6) was most commonly detected, followed by 1 case each of the following fusion gene partnerships: TPM3-ALK, KIF5B-ALK, CARS-ALK, THBS1-ALK, and a novel alteration, SLC12A2-ROS1. The excluded case was reclassified as spindle cell rhabdomyosarcoma after detection of a FUS-TFCP2 rearrangement and retrospective immunohistochemical confirmation of rhabdomyoblastic differentiation, illustrating an important diagnostic pitfall. Two IMT patients received targeted therapy with crizotinib, with a demonstrated radiographic response. One tumor recurred but none metastasized. These results add to the growing body of evidence that kinase fusions can be identified in the majority of IMTs and that molecular analysis can lead to increased diagnostic accuracy and broadened therapeutic options for patients.

Superficial ALK-rearranged myxoid spindle cell neoplasm: a cutaneous soft tissue tumor with distinctive morphology and immunophenotypic profile

Gene rearrangements involving the anaplastic lymphoma kinase (ALK) receptor tyrosine kinase gene have been identified in various neoplasms, including inflammatory myofibroblastic tumor and epithelioid fibrous histiocytoma. We present an ALK-rearranged cutaneous soft tissue tumor with unique morphologic and immunophenotypic features that are not shared by other entities with ALK rearrangements. The six cases involved two females and four males, aged 18-84 (mean 51) years old. Three tumors were on the back and three on the lower extremities (thigh, knee, shin); ranging from 0.5 to 5.6 (mean 2.1) cm. Four were confined to the dermis; two involved the subcutis. All six cases were characterized by the presence of spindled to ovoid cells arranged in concentric whorls and cords against a myxoid to myxohyaline stroma and relatively cellular aggregates of plump ovoid to epithelioid cells. Four cases showed distinct hyalinized blood vessels. Both cases that involved the subcutis showed peripheral lipofibromatosis-like areas. Tumor-infiltrating lymphocytes were absent to moderate. Severe cytologic atypia or conspicuous mitotic activity was not identified. Immunohistochemically, all tumors diffusely expressed ALK (D5F3) and CD34. All but one tumor was diffusely positive for S100 protein. All tumors were negative for EMA, AE1/AE3, SMA, and SOX10. Next-generation sequencing revealed ALK fusions with FLNA (3 cases), MYH10 (2 cases), and HMBOX1 (1 case) as the partner genes. In all six cases, the breakpoints involved exon 20 of ALK, which preserves the receptor tyrosine kinase domains of ALK in the fusion product. Of the four cases with limited follow-up information (2-18 months), none recurred. In conclusion, we report an ALK-rearranged cutaneous soft tissue tumor characterized by the presence of myxoid spindle cell whorls and cords, and co-expression of ALK, CD34, and frequently S100 protein, we term "superficial ALK-rearranged myxoid spindle cell neoplasm".

Identification and Validation of a Prognostic Signature for Prostate Cancer Based on Ferroptosis-Related Genes

Ferroptosis, an iron-dependent form of selective cell death, is involved in the development of many cancers. However, ferroptosis related genes (FRGs) in prostate cancer (PCa) are not been well studied. In this study, we collected the mRNA expression profiles and clinical information of PCa patients from TCGA and MSKCC databases. The univariate, LASSO, and multivariate Cox regression analyses were performed to construct a prognostic signature. Seven FRGs, AKR1C3, ALOXE3, ATP5MC3, CARS1, MT1G, PTGS2, and TFRC, were included to establish a risk model, which was validated in the MSKCC dataset. The results showed that the high-risk group was apparently correlated with copy number alteration load, tumor burden mutation, immune cell infiltration, mRNAsi, immunotherapy, and bicalutamide response. Moreover, we found that TFRC overexpression induced the proliferation and invasion of PCa cell lines in vitro. These results demonstrate that this risk model can accurately predict prognosis, suggesting that FRGs are promising prognostic biomarkers and potential drug targets in PCa patients.

ALK-negative lung inflammatory myofibroblastic tumor in a young adult: A case report and literature review of molecular alterations

RATIONALE

Inflammatory myofibroblastic tumor (IMT) is a rare mesenchymal tumor that is prevalent among children and adolescents. Surgery is the most important therapeutic approach for IMT and complete resection is recommended. Although 50% of IMTs show anaplastic lymphoma kinase (ALK) rearrangements, crizotinib has proven an effective therapeutic approach. However, the genetic landscape of this tumor is still not fully understood and treatment options are limited, especially in the majority of ALK-negative tumors.

PATIENT CONCERNS

We describe the clinical case of a healthy 18-year-old female in whom a pulmonary nodule was incidentally detected.

DIAGNOSES

Following a small increase in the size of the nodule, the patient underwent both 18FDG-PET/CT and 68Ga-PET/CT, resulting in a suspicion of bronchial hamartoma.

INTERVENTIONS

The patient underwent surgery and a salivary gland-like lung tumor was diagnosed.

OUTCOMES

After surgery, the patient was referred to our cancer center, where a review of the histology slides gave a final diagnosis of ALK-negative lung IMT. Given the histology, it was decided not to administer adjuvant therapy and the patient was placed in a 3-monthly follow-up program. The patient is still disease-free 2 years post-surgery.

LESSONS

Although there is no standard of care for the treatment of IMT, identifying genomic alterations could help to redefine the management of patients with negative-ALK disease. Our review of the literature on IMT and other kinase fusions revealed, in addition to ALK rearrangements, the potential association of ROS1, NTRK, RET, or PDGFR beta alterations with the tumor.

Near-complete response to low-dose ceritinib in recurrent infantile inflammatory myofibroblastic tumour

Background

Infantile inflammatory myofibroblastic tumour (IMT) is rare and the majority are driven by anaplastic lymphoma kinase (ALK) rearrangements. Previous literature on the use of ALK inhibitors in paediatric IMTs is extremely limited with no published literature on the use in infants. Crizotinib and ceritinib are two ALK inhibitors which are available and have been used in IMTs; however, ceritinib is much more affordable in the low- and middle-income country (LMIC) setting than crizotinib.

Case

An 11-month-old child, who had undergone surgery for mesenteric IMT at the age of 3 months, had an unresectable recurrence with soft tissue deposits in the subdiaphragmatic location abutting the spleen and paravesical location. As surgery would have entailed splenectomy and partial cystectomy, she was treated with low-dose ceritinib (300 mg/m2/day) with which she had a near-complete response without any toxicity.

Discussion and conclusion

This is the first report of the use of ceritinib at a lower dose for infantile IMT having immense practical applications for the low- and middle-income setting.

Pseudosarcomatous myofibroblastic proliferations of the urinary bladder are neoplasms characterized by recurrent FN1-ALK fusions

Pseudosarcomatous myofibroblastic proliferation is a descriptive term that designates a group of clinically indolent genitourinary lesions that most commonly arise in the urinary bladder. Given that pseudosarcomatous myofibroblastic proliferation may show morphologic overlap with inflammatory myofibroblastic tumor, the relationship, if any, between the two entities has been unclear. Moreover, pseudosarcomatous myofibroblastic proliferations are known to be positive for ALK immunohistochemistry in a subset of cases, although an inconsistent association with ALK rearrangement (ranging from 0 to 60%) has been reported. The objectives of this study were to determine the frequency of ALK rearrangement and to identify fusion partners using fluorescence in situ hybridization (FISH) and targeted RNA sequencing studies in a contemporary series of 30 pseudosarcomatous myofibroblastic proliferations of the urinary bladder, as well as to investigate ROS1 status by immunohistochemistry. ALK immunohistochemistry was positive in 70% (21/30) of pseudosarcomatous myofibroblastic proliferations; ROS1 immunohistochemistry was consistently negative (0/28). ALK rearrangements were detected by FISH in 86% (18/21) of cases, correlating with ALK immunohistochemical positivity in all but 3 cases. Of eight cases confirmed to be ALK rearranged by FISH, targeted RNA-sequencing detected FN1-ALK fusions in seven (88%) cases, which involved exons 20-26 of FN1 (5') and exon 18-19 of ALK (3'). In conclusion, ALK rearrangements are frequent in pseudosarcomatous myofibroblastic proliferations, typically involving exon 19, and FN1 appears to be a consistent fusion partner. Given the significant clinicopathologic differences between inflammatory myofibroblastic tumor and pseudosarcomatous myofibroblastic proliferation, our findings provide further support for classification of pseudosarcomatous myofibroblastic proliferation as a distinct clinicopathologic entity, and propose the alternate terminology "pseudosarcomatous myofibroblastic neoplasm of the genitourinary tract."

Spindle cell neoplasm with EML4-ALK gene fusion presenting as an intraosseous vertebral mass

In this article, we describe a spindle cell neoplasm harboring an EML4-ALK gene fusion presenting as an intraosseous vertebral mass with extension into the adjacent soft tissue in a 65-year-old man. Histologically, the lesion was characterized by the presence of monotonous, cytologically bland spindle cells with loose myxoedematous stroma and interspersed areas of amianthoid-like collagen fiber deposition. Immunohistochemistry demonstrated strong diffuse staining for CD34 and S100, with absent immunoreactivity for SOX10. At 1 year of follow-up after resection, there is no evidence of local recurrence or metastatic disease. This case adds to the clinical and pathologic spectrum of the recently described group of kinase fusion-positive spindle cell neoplasms and represents the first reported intra-osseous example. The presence of ALK rearrangement in this lesion represents a potential therapeutic target, if clinically indicated.

Efficacy and Resistance of ALK Inhibitors in Two Inflammatory Myofibroblastic Tumor Patients with ALK Fusions Assessed by Whole Exome and RNA Sequencing

We report two inflammatory myofibroblastic tumor (IMT) patients with ALK fusions (RRBP-ALK and TNS1-ALK, respectively). They both received tumor resection surgery and treatment with ALK inhibitors crizotinib followed by alectinib, and upon receiving each of the drugs, showed a brief response, then experienced recurrence or progression of the disease. During the treatment, whole exome sequencing (WES) and RNA sequencing (RNA-Seq) were applied to monitor potential drug-induced gene mutation and expression changes. A novel, secondary mutation in ALK exon 23 (L1196Q) was identified in patient 1 after alectinib resistance developed. Guided by this result, a newer ALK inhibitor, ceritinib was prescribed. The patient was able to achieve a partial response (PR) and is in good condition as of the manuscript date. On the contrary, there was no secondary mutation identified in ALK in patient 2 after drug resistance. While the expression of PTCH1, a negative regulator of the sonic hedgehog (SHH) signaling pathway, was significantly reduced at the time after the treatment with crizotinib before that of alectinib. The expression of PTCH1 was also reduced after the treatment with alectinib. It was reported that ALK can exert its biological functions partially by activating SHH signaling pathway. The down-regulation of PTCH1 suggests the compensatory activation of SHH pathway may cause resistance to ALK inhibitors in IMT. Going forward, monitoring gene mutation and expression changes through DNA and RNA sequencing will be able to offer opportunities to investigate potential mechanisms of drug resistance and will help to achieve precise prescription for better treatment outcomes.

Metastatic Low-Grade Sarcoma with CARS-ALK Fusion Dramatically Responded to Multiple ALK Tyrosine Kinase Inhibitors: A Case Report with Comprehensive Genomic Analysis

This article reports a case of advanced metastatic low-grade sarcoma. The patient was diagnosed with an inoperable large (14 × 12 cm) lesion on his neck in September 2015 and underwent two ineffective chemotherapies in the following 4 months. Interestingly, although several pathologists could not agree on the histopathological diagnosis, the precise molecular pathological diagnosis was obtained using next-generation sequencing (NGS) and finally brought excellent therapeutic effects. The patient was detected to have CARS-ALK fusion by NGS and then was successfully treated with crizotinib orally. He received surgical resection of primary and metastatic lesions after tumor shrinkage. The combined treatment brought a durable response for 40 months. Although the tumor recurred in July 2019, the patient has been responding well to the second-line ALK tyrosine kinase inhibitor alectinib to date. We performed whole genome sequencing on the patient's primary, metastatic, and recurrent tumors and did comprehensive genomic analysis. Furthermore, our analysis results revealed that a whole genome duplication event might have happened during tumorigenesis of this case. KEY POINTS: To our best knowledge, this is the first report of a very successful treatment with first- and second-line ALK tyrosine kinase inhibitors for CARS-ALK fusion-positive metastatic low-grade sarcoma. Molecular pathological result can guide precision treatment for sarcoma, even when the exact histopathology cannot be obtained. Multiple samples from this patient were analyzed using whole genome sequencing. Results provided detailed genomic characteristics and showed tumor evolution of this low-grade sarcoma case. A whole genome duplication event might have happened during tumorigenesis of this low-grade sarcoma case.

Intraarticular Inflammatory Myofibroblastic Tumor of the Left Knee With ALK-CARS Fusion Detected With Archer Fusionplex Sarcoma NGS Panel: Case Report and Literature Review

Inflammatory myofibroblastic tumor (IMT) is a lesion of intermediate biological potential with local recurrences and rare metastases found in multiple anatomical locations. We present a case of a pure intraarticular IMT of the knee, a location that has not been previously documented, with genetic confirmation of ALK-CARS fusion detected with next-generation sequencing. A 20-year-old healthy male was admitted to the orthopedic oncology department due to several months of pain and restriction in movement of his left knee. On magnetic resonance imaging, multiple intraarticular nodular lesions were seen. The patient underwent 2 synovectomies within the course of 1 year. The initial biopsy was interpreted as nodular fasciitis. The second biopsy revealed exuberant tissue displaying compact fascicles of spindle cells intermixed with myxoid areas in a background of inflammatory cells, highly suggestive for IMT. Due to the unusual intraarticular location, equivocal ALK immunostaining and the differential diagnosis with nodular fasciitis, we performed targeted next-generation sequencing using Archer FusionPlex Sarcoma panel, which can identify multiple fusions in a single assay. An ALK-CARS fusion was found, supporting the diagnosis of IMT. This report emphasizes the added value of broad molecular analysis in cases with unusual clinical presentation, equivocal immunohistochemistry, and a wide differential diagnosis.

Drug Discovery Targeting Anaplastic Lymphoma Kinase (ALK)

As a receptor tyrosine kinase of insulin receptor (IR) subfamily, anaplastic lymphoma kinase (ALK) has been validated to play important roles in various cancers, especially anaplastic large cell lymphoma (ALCL), nonsmall cell lung cancer (NSCLC), and neuroblastomas. Currently, five small-molecule inhibitors of ALK, including Crizotinib, Ceritinib, Alectinib, Brigatinib, and Lorlatinib, have been approved by the U.S. Food and Drug Administration (FDA) against ALK-positive NSCLCs. Novel type-I¹/₂ and type-II ALK inhibitors with improved kinase selectivity and enhanced capability to combat drug resistance have also been reported. Moreover, the "proteolysis targeting chimera" (PROTAC) technique has been successfully applied in developing ALK degraders, which opened a new avenue for targeted ALK therapies. This review provides an overview of the physiological and biological functions of ALK, the discovery and development of drugs targeting ALK by focusing on their chemotypes, activity, selectivity, and resistance as well as potential therapeutic strategies to overcome drug resistance.

Inflammatory myofibroblastic tumor of bone harboring an ALK gene amplification

Inflammatory myofibroblastic tumor (IMT) is a neoplastic proliferation of myofibroblastic/fibroblastic cells with a variable admixture of inflammatory cells. It primarily affects soft tissue and viscera of children and young adults. IMT occurring in bone is extremely rare. Approximately 50% of IMTs carry a clonal rearrangement of the anaplastic lymphoma kinase (ALK) gene, while other receptor tyrosine kinase gene rearrangements have been seen in a small subset of IMT. Herein, we report the first case of IMT which harbors an ALK gene amplification rather than a rearrangement thus resulting in overexpression of the protein, arising from the femur of a 24-year-old man. Our case provides a novel pathogenesis for IMT. An overview of cytogenetic abnormalities of IMT is also integrated into this report.

Discovery Stories of RET Fusions in Lung Cancer: A Mini-Review

In 2004, a chemical inhibitor of the kinase activity of EGFR was reported to be effective in a subset of lung cancer patients with activating somatic mutations of EGFR. It remained unclear, however, whether kinase fusion genes also play a major role in the pathogenesis of lung cancers. The discovery of the EML4-ALK fusion kinase in 2007 was a breakthrough for this situation, and kinase fusion genes now form a group of relevant targetable oncogenes in lung cancer. In this mini-review article, the discovery of REarrangement during Transfection fusions, the third kinase fusion gene in lung cancer, is briefly described.

Reprint of: Unusual non-neoplastic lesions of the lung

Many nonneoplastic conditions that may affect the lung are in reality rare or unusual manifestations of metabolic processes, inflammatory conditions, or unknown etiology. Because of their rarity, they can often be confused with malignant neoplasms. Familiarity with these conditions not only will expedite further treatment for these patients but also will avoid the process of more tests or unnecessary surgical procedures. The nomenclature for some of those conditions is still controversial. The clinical outcome of these conditions can be quite variable, with some patients surviving a long number of years and others eventually succumbing to the disease. We will limit our discussion in this review to four of these conditions, including inflammatory pseudotumor (inflammatory myofibroblastic tumor), placental transmogrification of lung, alveolar microlithiasis, and metastatic calcification. Although these lesions are not part of the gamut of neoplastic conditions affecting the lung, they are nonetheless important to recognize, as their outcome may not necessarily be an innocuous one.

Double amplifications of CDK4 and MDM2 in a gastric inflammatory myofibroblastic tumor mimicking cancer with local invasion of the spleen and diaphragm

Inflammatory myofibroblastic tumor (IMT) is currently recognized as an intermediate mesenchymal neoplasm. It can arise anywhere in the body, but it is particularly common in the lungs. Gastric IMT is very rare in adults. In this study, we report a case of a 68-year-old woman with IMT in the gastric cardia, with invasion into the spleen and diaphragm. Because of its location and aggressive clinical features, it was first mistaken for gastric cancer. However, pathology and immunohistochemistry were used to finally confirm the diagnosis of IMT after total resection of the tumor and spleen and partial resection of the diaphragm. In order to provide better understanding of this rare tumor, targeted next-generation sequencing (NGS) and IHC were performed to assess genetic and protein abnormalities of the tumor. Both IHC and NGS were found to be negative for ALK or other gene fusions. However, double amplification of CDK4 and MDM2 were found by NGS, and IHC also found CDK4 and MDM2 to be positive. To the best of our knowledge, this is the first gastric IMT report to show double invasion of the spleen and the diaphragm, and double amplification of CDK4 and MDM2 in IMT are also reported for the first time. This genomic aberration with protein overexpression is the most likely tumorigenic driver of this rare and aggressive tumor.

Tumor Resistance against ALK Targeted Therapy-Where It Comes From and Where It Goes

Anaplastic lymphoma kinase (ALK) is a validated molecular target in several ALK-rearranged malignancies, particularly in non-small-cell lung cancer (NSCLC), which has generated considerable interest and effort in developing ALK tyrosine kinase inhibitors (TKI). Crizotinib was the first ALK inhibitor to receive FDA approval for ALK-positive NSCLC patients treatment. However, the clinical benefit observed in targeting ALK in NSCLC is almost universally limited by the emergence of drug resistance with a median of occurrence of approximately 10 months after the initiation of therapy. Thus, to overcome crizotinib resistance, second/third-generation ALK inhibitors have been developed and received, or are close to receiving, FDA approval. However, even when treated with these new inhibitors tumors became resistant, both in vitro and in clinical settings. The elucidation of the diverse mechanisms through which resistance to ALK TKI emerges, has informed the design of novel therapeutic strategies to improve patients disease outcome. This review summarizes the currently available knowledge regarding ALK physiologic function/structure and neoplastic transforming role, as well as an update on ALK inhibitors and resistance mechanisms along with possible therapeutic strategies that may overcome the development of resistance.

Polymorphisms in CARS are associated with gastric cancer risk: a two-stage case-control study in the Chinese population

BACKGROUND

The cysteinyl transfer RNA synthetase gene (CARS) is located on chromosome band 11p15.5, which is an important tumor-suppressor gene region. Mutations in CARS have been identified in many kinds of cancers; however, evidence for a relationship between genetic variants in CARS and gastric cancer at the population level is still lacking. Thus, we explored the association of variants in CARS with gastric cancer using a two-stage case-control strategy in Chinese.

METHODS

We undertook a two-stage case-control study to investigate the association between polymorphisms in CARS and risk of gastric cancer with use of an Illumina Infinium^® BeadChip and an ABI 7900 system.

RESULTS

Four single nucleotide polymorphisms (SNPs) were significantly associated with gastric cancer risk in both the discovery stage and the validation stage after adjustment for age and sex. In addition, the combined results of the two stages showed these SNPs were related to gastric cancer risk (P _{false discovery rate} ≤ 0.001 for rs384,490, rs729662, rs2071101, and rs7394702). In silico analyses revealed that rs384490 and rs7394702 could affect transcription factor response elements or DNA methylation of CARS, and rs729662 was associated with the prognosis of gastric cancer. Additionally, expression quantitative trait loci analysis showed rs384490 and rs729662 might alter expression of CARS-related genes.

CONCLUSIONS

The potential functional SNPs in CARS might influence the biological functions of CARS or CARS-related genes and ultimately modify the occurrence and development of gastric cancer in Chinese. Further large-scale population-based studies or biological functional assays are warranted to validate our findings.

Targeting ALK: Precision Medicine Takes on Drug Resistance

Anaplastic lymphoma kinase (ALK) is a validated molecular target in several ALK-rearranged malignancies, including non-small cell lung cancer. However, the clinical benefit of targeting ALK using tyrosine kinase inhibitors (TKI) is almost universally limited by the emergence of drug resistance. Diverse mechanisms of resistance to ALK TKIs have now been discovered, and these basic mechanisms are informing the development of novel therapeutic strategies to overcome resistance in the clinic. In this review, we summarize the current successes and challenges of targeting ALK.

SIGNIFICANCE

Effective long-term treatment of ALK-rearranged cancers requires a mechanistic understanding of resistance to ALK TKIs so that rational therapies can be selected to combat resistance. This review underscores the importance of serial biopsies in capturing the dynamic therapeutic vulnerabilities within a patient's tumor and offers a perspective into the complexity of on-target and off-target ALK TKI resistance mechanisms. Therapeutic strategies that can successfully overcome, and potentially prevent, these resistance mechanisms will have the greatest impact on patient outcome. Cancer Discov; 7(2); 137-55. ©2017 AACR.

Intraocular inflammatory mass associated with lens-induced uveitis

Intraocular inflammatory tumefactions large enough to simulate neoplasms are uncommon. We report a patient with a large intraocular inflammatory mass composed of cells with features of histiocytes and myofibroblasts that was associated with lens-induced uveitis. The spindle cell mass appears to have arisen as an exaggerated response to exposed lens fibers. Although information from immunohistochemistry and cytogenetics has advanced the classification of inflammatory tumefactions, this case highlights the challenges in establishing the nature of these lesions.

Anaplastic large cell lymphoma: pathology, genetics, and clinical aspects

Anaplastic large cell lymphoma (ALCL) was first described in 1985 as a large-cell neoplasm with anaplastic morphology immunostained by the Ki-1 antibody, which recognizes CD30. In 1994, the nucleophosmin (NPM)-anaplastic lymphoma kinase (ALK) fusion receptor tyrosine kinase was identified in a subset of patients, leading to subdivision of this disease into ALK-positive and -negative ALCL in the present World Health Organization classification. Due to variations in morphology and immunophenotype, which may sometimes be atypical for lymphoma, many differential diagnoses should be considered, including solid cancers, lymphomas, and reactive processes. CD30 and ALK are key molecules involved in the pathogenesis, diagnosis, and treatment of ALCL. In addition, signal transducer and activator of transcription 3 (STAT3)-mediated mechanisms are relevant in both types of ALCL, and fusion/mutated receptor tyrosine kinases other than ALK have been reported in ALK-negative ALCL. ALK-positive ALCL has a better prognosis than ALK-negative ALCL or other peripheral T-cell lymphomas. Patients with ALK-positive ALCL are usually treated with anthracycline-based regimens, such as combination cyclophosphamide, doxorubicin, vincristine, and prednisolone (CHOP) or CHOEP (CHOP plus etoposide), which provide a favorable prognosis, except in patients with multiple International Prognostic Index factors. For targeted therapies, an anti-CD30 monoclonal antibody linked to a synthetic antimitotic agent (brentuximab vedotin) and ALK inhibitors (crizotinib, alectinib, and ceritinib) are being used in clinical settings.

TFE3-positive renal cell carcinomas are not always Xp11 translocation carcinomas: Report of a case with a TPM3-ALK translocation

Translocation-associated renal cell carcinoma (RCC) is a distinct subtype of RCC with gene rearrangements of the TFE3 or TFEB loci. The TFE3 gene is located at Xp11 and can fuse to a number of translocation partners, resulting in high nuclear expression of TFE3 protein. TFE3 immunostaining is often used as a surrogate marker for a TFE3 translocation. We report a case of an RCC that expressed TFE3 but showed only gain of TFE3 rather than a translocation. Moreover, this case had a t(1;2) translocation fusing ALK and TMP3, identical to that seen in inflammatory myofibroblastic tumour. There was resulting overexpression of ALK protein in a cytoplasmic and membranous pattern. The patient was not treated with chemotherapy but following regional nodal recurrence, an ALK inhibitor was added and the patient remains alive one year later. There are only rare reports of RCC with an ALK-TMP3 fusion, and these tumours can express TFE3 on some unknown basis not related to a TFE3 translocation. Any RCC positive for TFE3 and lacking a translocation should be tested for ALK expression and translocation. Recognition of this subtype of RCC will allow ALK inhibitor therapy to be added, in the hope of improving patient outcome.

Molecular characterization of inflammatory myofibroblastic tumors with frequent ALK and ROS1 gene fusions and rare novel RET rearrangement

Approximately 50% of conventional inflammatory myofibroblastic tumors (IMTs) harbor ALK gene rearrangement and overexpress ALK. Recently, gene fusions involving other kinases have been implicated in the pathogenesis of IMT, including ROS1 and in 1 patient PDGFRB. However, it remains uncertain whether the emerging genotypes correlate with clinicopathologic characteristics of IMT. In this study, we expand the molecular investigation of IMT in a large cohort of different clinical presentations and analyze for potential genotype-phenotype associations. Criteria for inclusion in the study were typical morphology and tissue availability for molecular studies. The lack of ALK immunoreactivity was not an excluding factor. As overlapping gene fusions involving actionable kinases are emerging in both IMT and lung cancer, we set out to evaluate abnormalities in ALK, ROS1, PDGFRB, NTRK1, and RET by fluorescence in situ hybridization. In addition, next-generation paired-end RNA sequencing and FusionSeq algorithm was applied in 4 cases, which identified EML4-ALK fusions in 2 cases. Of the 62 IMTs (25 children and 37 adults), 35 (56%) showed ALK gene rearrangement. Of note, EML4-ALK inversion was noted in 7 (20%) cases, seen mainly in the lung and soft tissue of young children including 2 lesions from newborns. There were 6 (10%) ROS1-rearranged IMTs, all except 1 presenting in children, mainly in the lung and intra-abdominally and showed a distinctive fascicular growth of spindle cells with long cell processes, often positive for ROS1 immunohistochemistry. Two of the cases showed TFG-ROS1 fusions. Interestingly, 1 adult IMT revealed a RET gene rearrangement, a previously unreported finding. Our results show that 42/62 (68%) IMTs are characterized by kinase fusions, offering a rationale for targeted therapeutic strategies. Interestingly, 90% of fusion-negative IMTs were seen in adults, whereas >90% of pediatric IMT showed gene rearrangements. EML4-ALK inversion and ROS1 fusions emerge as common fusion abnormalities in IMT, closely recapitulating the pattern seen in lung cancer.

Expression of ROS1 predicts ROS1 gene rearrangement in inflammatory myofibroblastic tumors

Inflammatory myofibroblastic tumor is a distinctive, rarely metastasizing mesenchymal neoplasm composed of fascicles of spindle cells with a prominent inflammatory infiltrate. Roughly 50% of inflammatory myofibroblastic tumors harbor ALK receptor tyrosine kinase gene rearrangements. Such tumors are usually positive for ALK by immunohistochemistry. The molecular pathogenesis of ALK-negative inflammatory myofibroblastic tumors is largely unknown. A recent study identified rearrangements of ROS1 (another tyrosine kinase receptor) in a subset of ALK-negative inflammatory myofibroblastic tumors. Immunohistochemistry for ROS1 has been shown to correlate with ROS1 rearrangement in lung adenocarcinomas. The purpose of this study was to determine whether immunohistochemistry for ROS1 could predict ROS1 rearrangement in inflammatory myofibroblastic tumor. In total, 30 inflammatory myofibroblastic tumors were evaluated, including 21 ALK-positive tumors (10 confirmed to harbor ALK rearrangements, with TPM3, CLTC, RANPB2, and FN1 fusion partners) and 9 ALK-negative tumors (including 2 known to harbor ROS1 rearrangements). Immunohistochemistry was performed on whole tissue sections following pressure cooker antigen retrieval using a rabbit anti-ROS1 monoclonal antibody. The results were scored as 'positive' or 'negative,' and the pattern of staining was recorded. Three ALK-negative inflammatory myofibroblastic tumors (including both tumors with known ROS1 rearrangements) showed immunoreactivity for ROS1, whereas all ALK-positive inflammatory myofibroblastic tumors were negative for ROS1. One ROS1-positive inflammatory myofibroblastic tumor (with YWHAE-ROS1 fusion) showed strong, diffuse cytoplasmic and nuclear staining; one case (with TFG-ROS1 fusion) showed weak, diffuse and dot-like cytoplasmic staining; and one case (fusion partner unknown) showed moderate, diffuse and dot-like cytoplasmic staining. Expression of ROS1 correlates with ROS1 gene rearrangement in inflammatory myofibroblastic tumor. These findings suggest that immunohistochemistry for ROS1 may be useful to support the diagnosis of a subset of inflammatory myofibroblastic tumors and may select some clinically aggressive cases for targeted therapy directed against ROS1.

Detecting and targetting oncogenic fusion proteins in the genomic era

The advent of widespread cancer genome sequencing has accelerated our understanding of the molecular aberrations underlying malignant disease at an unprecedented rate. Coupling the large number of bioinformatic methods developed to locate genomic breakpoints with increased sequence read length and a deeper understanding of coding region function has enabled rapid identification of novel actionable oncogenic fusion genes. Using examples of kinase fusions found in liquid and solid tumours, this review highlights major concepts that have arisen in our understanding of cancer pathogenesis through the study of fusion proteins. We provide an overview of recently developed methods to identify potential fusion proteins from next-generation sequencing data, describe the validation of their oncogenic potential and discuss the role of targetted therapies in treating cancers driven by fusion oncoproteins.

Novel ALK inhibitors in clinical use and development

Anaplastic lymphoma kinase 1 (ALK-1) is a member of the insulin receptor tyrosine kinase family. ALK-1 was initially found in anaplastic large cell lymphoma (ALCL). ALK mutations have also been implicated in the pathogenesis of non-small cell lung cancer (NSCLC) and other solid tumors. Multiple small molecule inhibitors with activity against ALK and related oncoproteins are under clinical development. Two of them, crizotinib and ceritinib, have been approved by FDA for treatment of locally advanced and metastatic NSCLC. More agents (alectinib, ASP3026, X396) with improved safety, selectivity, and potency are in the pipeline. Dual inhibitors targeting ALK and EGFRm (AP26113), TRK (TSR011), FAK (CEP-37440), or ROS1 (RXDX-101, PF-06463922) are under active clinical development.

Advances in understanding the pathogenesis of systemic anaplastic large cell lymphomas

The currently used 2008 World Health Organization classification recognizes two types of systemic anaplastic large T cell lymphoma according to ALK protein expression in tumour cells. First, the 'anaplastic large cell lymphoma, ALK positive' (ALK(+) ALCL) that is characterized by the presence of ALK gene rearrangements and consequent ALK protein expression, and, second, the 'anaplastic large cell lymphoma, ALK negative' (ALK(-) ALCL) that is a provisional entity lacking ALK protein expression but cannot be distinguished morphologically from ALK(+) ALCL. In this review we summarize the current knowledge on the genetic lesions and biological features that underlie the pathogenesis of ALK(+) and the ALK(-) ALCL and that can lead to the use of targeted anti-cancer agents.

A rare tumor of trachea: Inflammatory myofibroblastic tumor diagnosis and endoscopic treatment

Inflammatory myofibroblastic tumors (IMTs) are rare childhood neoplasms, with benign clinical course. Although etiology of IMTs are not clear, recent studies have reported that IMT is a true neoplasm rather than a reactive or inflammatory lesion. IMTs are rarely seen in adults and tracheal involvement is also rare both in adults and also in children. We describe a 16-year old female patient who was misdiagnosed and treated as asthma in another center for a few months and presented with acute respiratory distress due to upper airway obstruction. Computerized tomography (CT) of the chest and rigid bronchoscopy revealed a mass lesion that was nearly totally obliterating tracheal lumen. Bronchoscopic resection was performed under general anesthesia and the final pathological diagnosis was tracheal IMT.

An Unusual Case of Systemic Inflammatory Myofibroblastic Tumor with Successful Treatment with ALK-Inhibitor

Systemic inflammatory myofibroblastic tumor is an exceedingly rare entity. A 45-year-old Hispanic female presented with a 6-month history of left-sided thigh pain, low back pain, and generalized weakness. PET/CT scan revealed abnormal activity in the liver, adrenal gland, and pancreas. MRI of the abdomen demonstrated two 6-7 cm masses in the liver. MRI of the lumbar spine demonstrated lesions in the L2 to L4 spinous processes, paraspinal muscles, and subcutaneous tissues, as well as an 8 mm enhancing intradural lesion at T11, all thought to be metastatic disease. A biopsy of the liver showed portal tract expansion by a spindle cell proliferation rich in inflammation. Tumor cells showed immunoreactivity for smooth muscle actin and anaplastic lymphoma kinase 1 (ALK1). Tissue from the L5 vertebra showed a process histologically identical to that seen in the liver. FISH analysis of these lesions demonstrated an ALK (2p23) gene rearrangement. The patient was successfully treated with an ALK-inhibitor, Crizotinib, and is now in complete remission. We present the first reported case, to our knowledge, of inflammatory myofibroblastic tumor with systemic manifestations and ALK translocation. This case is a prime example of how personalized medicine has vastly improved patient care through the use of molecular-targeted therapy.

Anaplastic lymphoma kinase (ALK) inhibitors: a review of design and discovery

This review elucidates the hit-to-drug evolution design of three ALK inhibitors.

Low-grade myofibroblastic proliferations of the urinary bladder

CONTEXT

Myofibroblastic proliferations of the urinary bladder, which share some similarities with nodular fasciitis, were first reported in 1980. Since then, they have had several designations, the most frequently used being inflammatory myofibroblastic tumor. Based on both histopathologic and prognostic grounds, some authors prefer the term pseudosarcomatous myofibroblastic proliferation, at least for some of the proliferations. These same scientists also assimilate the so-called postoperative spindle cell nodules with the pseudosarcomatous myofibroblastic proliferations. Little is known about these low-grade myofibroblastic proliferations.

OBJECTIVES

To review the literature about low-grade myofibroblastic proliferations occurring in the urinary bladder.

DATA SOURCES

Textbooks and literature review. We obtained most of the clinicopathologic peculiarities from a patient population composed of the most-relevant, previously reported cases.

CONCLUSIONS

The low-grade myofibroblastic proliferations of the urinary bladder are rare lesions affecting males more often than they do females. The most-common signs and symptoms are hematuria and dysuria. Histopathologically, they are spindle cell proliferations in a loose myxoid stroma, even though compact proliferations or hypocellular fibrous patterns can be found. Immunohistochemistry is quite nonspecific, except for ALK-1 positivity (20%-89%). Fluorescence in situ hybridization has demonstrated clonal genetic aberrations involving the ALK gene in 50% to 60% of cases. After surgery, only 6% of patients experience local recurrence, without metastases or deaths from the disease. Malignant transformation has been reported exceptionally. These myofibroblastic proliferations are probably part of a continuum with, at one end, benign pseudosarcomatous proliferations and, at the opposite end, more-aggressive lesions. Because of the frequently indolent clinical course, aggressive treatment would be unjustified.

ALK gene amplification is associated with poor prognosis in colorectal carcinoma

BACKGROUND

Recently, the anaplastic lymphoma kinase (ALK) has been found to be altered in several solid and haematological tumours. ALK gene copy number changes and mutations in colorectal cancers (CRCs) are not well characterised. We aimed to study the prevalence of ALK copy number changes, translocations, gene mutations and protein expression in 770 CRC patients, and correlate these findings with molecular and clinico-pathological data.

METHODS

ALK gene copy number variations and ALK expression were evaluated by fluorescence in situ hybridisation (FISH) and immunohistochemistry, respectively.

RESULTS

Translocations of the ALK gene were not observed; 3.4% (26 out of 756) of the CRC patients tested had an increase in ALK gene copy number either amplification or gain. Interestingly, increased ALK gene copy number alteration was associated with poor prognosis (P=0.0135) and was an independent prognostic marker in multivariate Cox proportional hazards model. The study reveals a significant impact of ALK gene copy number alterations on the outcome of patients with CRC.

CONCLUSION

The findings of our study highlight a potential role of targeting ALK in advanced CRCs by using ALK FISH and ALK IHC as a screening tool to detect ALK alterations. Based on these findings, a potential role of ALK inhibitor as a therapeutic agent in a subset of CRC merits further investigation.

Mechanistic insight into ALK receptor tyrosine kinase in human cancer biology

The burgeoning field of anaplastic lymphoma kinase (ALK) in cancer encompasses many cancer types, from very rare cancers to the more prevalent non-small-cell lung cancer (NSCLC). The common activation of ALK has led to the use of the ALK tyrosine kinase inhibitor (TKI) crizotinib in a range of patient populations and to the rapid development of second-generation drugs targeting ALK. In this Review, we discuss our current understanding of ALK function in human cancer and the implications for tumour treatment.