Colorectal Adenocarcinomas Harboring ALK Fusion Genes: A Clinicopathologic and Molecular Genetic Study of 12 Cases and Review of the Literature

Primary mucinous adenocarcinoma of the urethra: A clinicopathological analysis of 35 cases

AIM

Primary mucinous adenocarcinoma of the urethra represents an extremely rare entity. We sought to characterise further these tumours' clinicopathological, immunohistochemical and molecular features.

METHODS AND RESULTS

Thirty-five cases were identified, occurring in 18 males and 17 females. The mean age at diagnosis was 65 years (28-89 years). The main presentation symptoms were haematuria and urinary outlet obstruction. Microscopic analysis revealed that all 35 tumours have stromal dissection by mucin. Ten tumours showed villoglandular dysplasia, nine showed mucinous metaplasia, two showed adenocarcinoma in situ and four showed signet ring cell features. All tumours were immunopositive for CEA, while immunonegative for nuclear β-catenin; 19 of 23 (83%) expressed high molecular weight cytokeratin; 19 of 33 (58%) CK7; 28 of 34 (82%) CK20; 32 of 35 (91%) CDX2; 22 of 27 (81%) cadherin-17 (CDH-17); 26 of 29 (90%) SATB2; and one of 31 (3%) GATA3. Mismatch repair gene products, including MLH1, PMS2, MSH2 and MSH6, were immunopositive, suggesting the MSI-low genotype of mucinous adenocarcinoma of the urethra. BRAF V600E and ALK rearrangements were not detected. During the mean follow-up of 20 months, nine patients either developed distant metastasis or succumbed to the illness.

CONCLUSION

Our study, encompassing the most extensive series of 35 cases of primary mucinous adenocarcinoma of the urethra, provides crucial insights into its precise diagnosis, management and potential targeted treatments. We found a greater CDX2, SATB2 and CDH17 sensitivity in these urethral tumours for the first time, to our knowledge. We identified characteristics such as an MSI-low profile, non-V600E BRAF mutations and an absence of ALK rearrangements.

Reticular Myxoid Odontogenic Neoplasm with Novel STRN::ALK Fusion: Report of 2 Cases in 3-Year-Old Males

Odontogenic tumors represent a collection of entities ranging from hamartomas to destructive benign and malignant neoplasms. Occasionally, pathologists encounter gnathic lesions which clearly exhibit an odontogenic origin but do not fit within the confines of established diagnoses. Here, we describe two such odontogenic tumors, both affecting 3-year-old males. Each case presented as a destructive, radiolucent mandibular lesion composed of mesenchymal cells, some with unique multi-lobed nuclei, frequently arranged in a reticular pattern and supported by a myxoid stroma with focal laminations. Production of odontogenic hard tissues was also seen. Because of their unique microscopic features, both cases were investigated by next-generation sequencing and found to harbor the same STRN::ALK oncogene fusion. To our knowledge, these cases represent the first report of an odontogenic tumor with a STRN::ALK gene rearrangement. We propose the possibility that this neoplasm could be separate from other known odontogenic tumors. Both patients were treated with surgical resection and reconstruction. The prognosis of patients with this entity is currently uncertain but shall become more apparent over time as more cases are identified and followed.

Tyrosine kinase alterations in colorectal cancer with emphasis on the distinct clinicopathological characteristics

AIMS

Tyrosine kinase (TK) alterations, such as anaplastic lymphoma kinase (ALK) fusion, neurotrophic tyrosine receptor kinase (NTRK) fusion, c-ros oncogene 1 (ROS1) fusion and mesenchymal-epithelial transition factor (MET) exon 14 skipping, have been reported in colorectal cancers (CRC). We have previously reported CRCs with NTRK fusion among our cohort. However, their clinicopathological features have not been fully elucidated.

METHODS AND RESULTS

Tissue microarray (TMA)-based immunohistochemistry (IHC) was performed on 951 CRC lesions from 944 patients. IHC was evaluated as positive or negative for ALK and ROS1 and 0 to 3+ for c-MET. For ALK and ROS1 IHC-positive cases, RNA-based imbalanced gene expression assays, Archer FusionPlex assays and reverse transcription-polymerase chain reaction (RT-PCR) followed by Sanger sequencing were performed. For c-MET IHC 3+ cases, RT-PCR followed by Sanger sequencing were performed. ALK IHC was positive in three cases (0.2%) and all showed imbalanced ALK gene expression. The following ALK fusions were confirmed: EML4 (exon 21)::ALK (exon 20), EML4 (exon 6)::ALK (exon 19) and HMBOX1 (exon 6)::ALK (exon 20). Two showed microsatellite instability-high/mismatch repair (MMR)-deficient, and all were located in the right colon. ROS1 IHC was positive in one case; however, imbalanced expression and ROS1 fusion was negative. Forty-two cases (4.4%) showed c-MET IHC3+. MET exon 14 skipping was confirmed in nine cases. All cases were microsatellite stable/MMR-proficient, and eight were located in the left colon and rectum.

CONCLUSIONS

CRCs with these TK alterations had distinct clinicopathological features. Together with our previous study, 15 cases (1.6%) harboured targetable TK alterations (three NTRK fusion, three ALK fusion, nine MET exon 14 skipping).

Case Report: A rare case of non-small cell lung cancer with STRN-ALK fusion in a patient in very poor condition treated with first-line ensartinib

Several cases of STRN-ALK fusion have been reported, and some anaplastic lymphoma kinase (ALK) inhibitors have been shown to be effective for treatment. Nevertheless, no cases of COVID-19 leading to heart failure and respiratory failure have been reported in people older than 70 years treated with ALK inhibitors. The present case report describes a 70-year-old patient with usual chronic obstructive pulmonary disease, diabetes, depression, and carotid plaque disease. Next-generation sequencing of tissue obtained by puncture biopsy revealed a STRN-ALK mutation accompanied by a TP53 mutation. The patient was treated with ensartinib and developed COVID-19 leading to heart failure and respiratory failure; nevertheless, he had a good clinical outcome and exhibited high treatment tolerability.

A narrative review of methods for the identification of ALK fusions in patients with non-small cell lung carcinoma

Background and Objective

This narrative review is intended to provide pragmatic knowledge of current methods for the search of anaplastic lymphoma kinase (ALK) fusions in patients with non-small cell lung carcinoma (NSCLC). This information is very timely, because a recent survey has identified that almost 50% of patients with advanced NSCLC were not candidates for targeted therapies because of biomarker testing issues.

Methods

PubMed was searched from January 1st, 2012 to February 28th, 2023 using the following keywords: "ALK" and "lung", including reviews and our own work.

Key Content and Findings

Testing rates have not reached 85% among patients' candidates to ALK inhibition. The advantages and disadvantages of the different analytical options [immunohistochemistry (IHC), fluorescence in situ hybridization (FISH), real-time polymerase chain reaction and next-generation sequencing (NGS)] are discussed. The key factor for success in ALK testing is a deep understanding of the concept of "molecular redundancy". This notion has been recommended and endorsed by all the major professional organizations in the field and can be summarized as follows: "laboratories should ensure that test results that are unexpected, discordant, equivocal, or otherwise of low confidence are confirmed or resolved using an alternative method or sample". In-depth knowledge of the different ALK testing methodologies can help clinical and molecular tumor boards implement and maintain sensible algorithms for a rapid and effective detection of predictive biomarkers in patients with NSCLC.

Conclusions

Multimodality testing has the potential to increase both the testing rate and the accuracy of ALK fusion identification.

Mutations in Classical Signaling Pathways and Their Functional Impact in Microsatellite Instability High Colorectal Cancer

Aims: Colorectal carcinomas with microsatellite instability high (MSI-H) are a distinctive group among colorectal cancers (CRCs). This study investigated the mutations of genes in the common signaling pathways and their potential clinical implications in MSI-H CRC. Materials and Methods: Twenty-five MSI-H tumors were selected from 384 primary CRCs, and the related clinical and pathological information were also collected from medical records. A commercial kit was used to detect the mutational status of crucial oncogenes within these tumors using next generation sequencing (NGS). Fluorescence in situ hybridization and immunohistochemistry were used to validate the NGS findings. Result: In the present study, MSI-H cases accounted for 6.51% of primary CRCs, with special clinicopathological features. NGS showed that the average number of mutations per tumor in the target genes evaluated was 3.36 and ranged from 1 to 9. In total, there were 17 cases (68%) with mutations in the RAS-RAF pathway and 18 cases (72%) with mutations in the PI3K pathway among the MSI-H CRCs. The remaining two cases included an EMAP Like 4-ALK Receptor Tyrosine Kinase (EML4-ALK) fusion and one with a Erb-B2 Receptor Tyrosine Kinase 2 (ERBB2) missense mutation. Conclusion: This study found multiple variants within different signaling pathways that were mutually present in MSI-H CRCs, suggesting that such a heterogeneous group of tumors requires complex treatment responses. Thus, additional clinical molecular testing is recommended for such patients, such as NGS, to inform the appropriate treatment strategies.

Crizotinib Nanomicelles Synergize with Chemotherapy through Inducing Proteasomal Degradation of Mutp53 Proteins

TP53 missense mutations that express highly stabilized mutant p53 protein (mutp53) driving tumorigenesis have been witnessed in a considerable percentage of human cancers. The attempt to induce degradation of mutp53 has thus been an attractive strategy to realize precise antitumor therapy, but currently, there has been no FDA-approved medication for mutp53 cancer. Herein, we discovered a small molecule compound crizotinib, an FDA-approved antitumor drug, exhibited outstanding mutp53-degrading capability. Crizotinib induced ubiquitination-mediated proteasomal degradation of wide-spectrum mutp53 but not the wild-type p53 protein. Degradation of mutp53 by crizotinib eliminated mutp53-conferred gain-of-function (GOF), leading to reduced cell proliferation, migration, demise, and cell cycle arrest, as well as enhanced sensitivity to doxorubicin-elicited killing in mutp53 cancer. To alleviate the side effects and improve the therapeutic effect, we adopted poly(ethylene glycol)-polylactide-co-glycolide (PEG-PLGA) nanomicelles to deliver the hydrophobic drugs doxorubicin and crizotinib, demonstrating that crizotinib nanomicelles effectively enhanced doxorubicin-elicited anticancer efficacy in a p53^Y220C pancreatic cancer in vitro and in vivo via mutp53 degradation induced by crizotinib, manifesting its promising application in clinical practice. Our work therefore revealed that crizotinib exerted significant synergistic chemotherapy with doxorubicin and suggested a novel combination therapeutic strategy for targeting p53 cancer in further clinical application.

Molecular characterization of adenocarcinomas arising in the urinary bladder following augmentation cystoplasty: a multi-institutional study

Development of malignancy is a rare complication following augmentation cystoplasty, and the majority of tumors observed in this setting are adenocarcinomas. Here, we sought to genetically profile these tumors by targeted DNA sequencing of a multi-institutional cohort of adenocarcinomas that developed in the urinary bladder following augmentation cystoplasty. Carcinomas arising in the urinary bladder of patients with history of augmentation cystoplasty were obtained from 4 major academic institutions, with cases diagnosed as urothelial carcinoma excluded from the study. The cases were analyzed using a DNA sequencing panel that includes 529 genes and genome-wide copy number assessment. The most frequently altered genes included TP53, KRAS, and MYC, and the vast majority of cases demonstrated mutational profiles consistent with gastrointestinal adenocarcinomas. One case demonstrated an EML4::ALK fusion together with an MSH3 frameshift mutation and hypermutated phenotype, characteristic of a rare but aggressive subtype of colorectal adenocarcinoma that may benefit from targeted ALK inhibition therapy. Importantly, six other tumors in the cohort also had potentially targetable molecular alterations, involving ATM (2 cases), BRCA1 (2 cases), EGFR (1 case), and ERBB2 (1 case). To our knowledge, this study represents the most comprehensive molecular characterization to date of adenocarcinomas arising in the urinary bladder following augmentation cystoplasty. Despite the unique environment of the augmented tissue, the resulting tumors demonstrate a spectrum of driver mutations similar to that of primary gastrointestinal adenocarcinomas. Importantly, molecular alterations potentially amenable to targeted therapy were identified in the majority of cases.

Therapeutic Advances of Rare ALK Fusions in Non-Small Cell Lung Cancer

Non-small cell lung cancer (NSCLC) accounts for approximately 85% of all lung cancer cases and is the leading cause of cancer-related death. Despite advances in chemotherapy and immunotherapy, the prognosis for advanced patients remains poor. The discovery of oncogenic driver mutations, such as anaplastic lymphoma kinase (ALK) mutations, means that a subset of patients has opportunities for targeted therapy. With the improvement of genetic testing coverage, more and more ALK fusion subtypes and ALK partners have been discovered, and more than 90 rare ALK fusion subtypes have been found in NSCLC. However, unlike the common fusion, echinoderm microtubule-associated protein-like 4 (EML4)-ALK, some rare ALK fusions such as striatin (STRN)-ALK and huntingtin interacting protein 1 (HIP1)-ALK, etc., the large-scale clinical data related to its efficacy are still immature. The clinical application of ALK-tyrosine kinase inhibitors (ALK-TKIs) mainly depends on the positivity of the ALK gene, regardless of the molecular characteristics of the fusion partner. Recent clinical studies in the ALK-positive NSCLC population have demonstrated differences in progression-free survival (PFS) among patients based on different ALK fusion subtypes. This article will introduce the biological characteristics of ALK fusion kinase and common detection methods of ALK fusion and focus on summarizing the differential responses of several rare ALK fusions to ALK-TKIs, and propose corresponding treatment strategies, so as to better guide the application of ALK-TKIs in rare ALK fusion population.

NTRK Fusions in 1113 Solid Tumors in a Single Institution

Most NTRK fusions occur at very low frequencies in various common cancers. Recent recommendations on NTRK testing recommend immunohistochemistry (IHC) as the initial test for tumor types with a low frequency of NTRK fusions. This study investigated the accuracy of an IHC assay to detect NTRK fusions and characterize the clinicopathological and molecular features of NTRK-rearranged tumors. This retrospective study was conducted on 1113 solid tumor samples known to harbor no oncogenic driver alterations, including 510 non-small cell lung cancers (NSCLC), 503 colorectal cancers (CRC), and 79 inflammatory myofibroblastic tumors (IMT). Additionally, 21 ALK expression-positive cases were included. TRK expression was evaluated using a pan-Trk IHC assay, and positive cases were validated using NGS. TRK expression was observed in three NSCLCs (0.6%), six CRCs (1.2%), and six IMTs (6%). NTRK fusions were finally detected in two NSCLCs (0.4%), six CRCs (1.2%), and one IMT (1%). In NSCLC and CRC, the majority of NTRK fusions were readily discernible due to diffuse moderate-to-strong cytoplasmic staining on pan-Trk IHC. In IMT, focal weak nuclear staining indicated the presence of NTRK fusion. Therefore, the utility of pan-Trk IHC should be assessed considering that the difference in performance depends on tumor type.

Roles of fusion genes in digestive system cancers: dawn for cancer precision therapy

For advanced and advanced tumors of the digestive system, personalized, precise treatment could be a lifesaving medicine. With the development of next-generation sequencing technology, detection of fusion genes in solid tumors has become more extensive. Some fusion gene targeting therapies have been written into the guidelines for digestive tract tumors, such as for neurotrophic receptor tyrosine kinase, fibroblast growth factor receptor 2. There are also many fusion genes being investigated as potential future therapeutic targets. This review focuses on the current detection methods for fusion genes, fusion genes written into the digestive system tumor guidelines, and potential fusion gene therapy targets in different organs to discuss the possibility of clinical treatments for these targets in digestive system tumors.

Gene fusions and oncogenic mutations in MLH1 deficient and BRAFV600E wild-type colorectal cancers

Gene fusions can act as oncogenic drivers and offer targets for cancer therapy. Since fusions are rare in colorectal cancer (CRC), their universal screening seems impractical. Our aim was to investigate gene fusions in 62 CRC cases with deficient MLH1 (dMLH1) and BRAFV600E wild-type (wt) status from a consecutive real-life series of 2079 CRCs. First, gene fusions were analysed using a novel FusionPlex Lung v2 RNA-based next-generation sequencing (NGS) panel, and these results were compared to a novel Idylla GeneFusion assay and pan-TRK immunohistochemistry (IHC). NGS detected seven (7/62, 11%) NTRK1 fusions (TPM3::NTRK1, PLEKHA6::NTRK1 and LMNA::NTRK1, each in two cases, and IRF2BP2::NTRK1 in one case). In addition, two ALK, four RET and seven BRAF fusions were identified. Idylla detected seven NTRK1 expression imbalances, in line with the NGS results (overall agreement 100%). Furthermore, Idylla detected the two NGS-identified ALK rearrangements as one specific ALK fusion and one ALK expression imbalance, whilst only two of the four RET fusions were discovered. However, Idylla detected several expression imbalances of ALK (n = 7) and RET (n = 1) that were found to be fusion negative with the NGS. Pan-TRK IHC showed clearly detectable, fusion partner-dependent staining patterns in the seven NTRK1 fusion cases. Overall agreement for pan-TRK antibody clone EPR17341 was 98% and for A7H6R 100% when compared to the NGS. Of the 62 CRCs, 43 were MLH1 promoter hypermethylated (MLH1ph) and 39 were RASwt. All fusion cases were both MLH1ph and RASwt. Our results show that kinase fusions (20/30, 67%) and most importantly targetable NTRK1 fusions (7/30, 23%) are frequent in CRCs with dMLH1/BRAFV600Ewt/MLH1ph/RASwt. NGS was the most comprehensive method in finding the fusions, of which a subset can be screened by Idylla or IHC, provided that the result is confirmed by NGS.

Tackling Refractory Metastatic Colorectal Cancer: Future Perspectives

Substantial improvements have characterized the systemic treatment of metastatic colorectal cancer (mCRC) over the past 20 years. Besides strong evidence that supports the use of RAS and BRAF status as prognostic and predictive indicators of disease and response, novel technologies have made possible the incorporation of emerging biomarkers for the management of mCRC. On one hand, the discovery of point mutations, amplifications, fusions, and gene expression profiles highlights the genomic and dynamic complexity of CRC. On the other, such discoveries are leading to newer biomarker-driven strategies that add to existing anti-epidermal growth factor receptor (EGFR) and anti-angiogenic approaches. In addition, the availability of a wide molecular profiling has relevant implications for patient prognosis and treatment benefits. Here, we will review the molecular underpinnings and clinical data supporting novel targeted treatments under development for refractory mCRC harboring BRAF mutations, KRAS G12C mutations, HER2 amplification, and less common molecular alterations, such as the re-arrangements of NTRK, ALK, and ROS1. Additionally, we will discuss novel strategies driving the rechallenge of EGFR antibodies and the incorporation of newer anti-angiogenic agents in the therapeutic armamentarium.

NTRK fusion-positive colorectal cancer in Japanese population

ALK, ROS1 and NTRK fusions are involved in the tumorigenesis of various organs, including colorectal cancer. This study aims to clarify the prevalence of these fusions in colorectal cancer in the Japanese population. Immunohistochemical analysis of 1012 specimens of colorectal cancer revealed two NTRK-positive cases (0.2%) whereas no ALK- or ROS1-positive cases were identified. Reverse transcription polymerase chain reaction (RT-PCR) detected an LMNA-NTRK1 fusion in a case of adenosquamous carcinoma and a TPM3-NTRK1 fusion in a case of tubular adenocarcinoma. Both NTRK1 fusion-positive cases lacked activating mutations in KRAS and BRAF and were mismatch repair-deficient with loss of MLH1 and PMS2 expression and MLH1 promoter methylation. Our results show that receptor tyrosine kinase fusions are rare but present in colorectal cancers in Japanese patients, with a prevalence similar to that reported in other countries.

Concomitant Pathogenic Mutations and Fusions of Driver Oncogenes in Tumors

Driver oncogene alterations have always been one of leading causes in the process of occurrence and development of tumors. And the effects of driver oncogene alterations on tumorigenesis and progression in different kinds of tumors have been studied heatedly. And the roles that the driver oncogenes alterations play have been elucidated clearly in previous studies. The phenomenon of concomitant driver oncogenes mutations and driver genes fusions has gained much concentration in the past two decades. And a growing number of studies reported this phenomenon, either coexistence or mutually exclusivity. Here we reviewed on the phenomenon of concomitant mutations in three common types of carcinomas—lung cancer, thyroid cancer, and leukemia, which have been studied relatively more detailed and more general compared with others.

βII spectrin (SPTBN1): biological function and clinical potential in cancer and other diseases

βII spectrin, the most common isoform of non-erythrocyte spectrin, is a cytoskeleton protein present in all nucleated cells. Interestingly, βII spectrin is essential for the development of various organs such as nerve, epithelium, inner ear, liver and heart. The functions of βII spectrin include not only establishing and maintaining the cell structure but also regulating a variety of cellular functions, such as cell apoptosis, cell adhesion, cell spreading and cell cycle regulation. Notably, βII spectrin dysfunction is associated with embryonic lethality and the DNA damage response. More recently, the detection of altered βII spectrin expression in tumors indicated that βII spectrin might be involved in the development and progression of cancer. Its mutations and disorders could result in developmental disabilities and various diseases. The versatile roles of βII spectrin in disease have been examined in an increasing number of studies; nonetheless, the exact mechanisms of βII spectrin are still poorly understood. Thus, we summarize the structural features and biological roles of βII spectrin and discuss its molecular mechanisms and functions in development, homeostasis, regeneration and differentiation. This review highlight the potential effects of βII spectrin dysfunction in cancer and other diseases, outstanding questions for the future investigation of therapeutic targets. The investigation of the regulatory mechanism of βII spectrin signal inactivation and recovery may bring hope for future therapy of related diseases.