ALK-positive cancer: still a growing entity

Prognostic value of ALK overexpression and molecular abnormalities in high-grade serous ovarian carcinoma

BACKGROUND

ALK receptor tyrosine kinase (ALK) aberrations have an established role in pathogenesis of many neoplasms, but their clinical significance in high grade serous ovarian carcinoma (HGSOC) is unclear.

OBJECTIVE

To analyse the frequency of ALK overexpression, molecular abnormalities of ALK, and their impact on the progression-free survival (PFS) and overall survival (OS) in HGSOC.

METHODS

Protein expression was examined by immunohistochemistry (IHC) using three different clones of anti-ALK antibody. The presence of translocations was analysed using fluorescent in situ hybridization. Next-generation sequencing was used for studying the copy number variation, as well as point mutation and translocations involving other commonly rearranged genes.

RESULTS

ALK overexpression was demonstrated in up to 52% of tumours, whereas ALK copy gains in 8.2%, with no clear impact on survival. ALK point mutations were identified in 13 tumours (8.9%), with 3 belonging to the class IV showing significantly better OS. A trend suggesting better PFS was also noticed in these cases. Additionally, three gene fusions were found: ERBB2-GRB7, PRKCA-BRCA1 and SND1-BRAF, none of which has been previously described in HGSOC.

CONCLUSIONS

HGSOC harbouring activating ALK mutations might be associated with a better survival, while ALK overexpression and ALK amplification does not impact the prognosis.

Activity of ALK Inhibitors in Renal Cancer with ALK Alterations: A Systematic Review

Renal cell carcinoma (RCC) associated with anaplastic lymphoma kinase (ALK) gene rearrangements (ALK-RCC) is currently considered an “emerging or provisional” tumor entity by the last World Health Organization classification published in 2016. Although several studies assessing ALK-RCC’s clinical and histological characteristics have been published in recent years, only a few publications have evaluated the activity of ALK inhibitors (ALK-i) in this subgroup of patients. Considering the well-recognized efficacy of this evolving class of targeted therapies in other ALK-positive tumors, we conducted a systematic review to evaluate the reported activity of ALK-i in the ALK-RCC subtype. MEDLINE was searched from its inception to 7 January 2022 for case reports and case series on adult metastatic ALK-RCC patients treated with ALK-i whose therapeutic outcomes were available. A virtual cohort of ALK-RCC patients was created. Our results showed a favorable activity of first- and second-generation ALK-i in pretreated ALK-RCC patients in terms of either radiological response or performance status improvement. We hope that the present work will prompt the creation of large, multi-institutional clinical trials to confirm these promising early data.

ALK alterations in salivary gland carcinomas

Salivary gland carcinomas represent a heterogeneous group of poorly characterized head and neck tumors. The purpose of this study was to evaluate ALK gene and protein aberrations in a large, well-characterized cohort of these tumors. A total of 182 salivary gland carcinomas were tested for anaplastic lymphoma kinase (ALK) positivity by immunohistochemistry (IHC) using the cut-off of 10% positive cells. ALK positive tumors were subjected to FISH analysis and followed by hybrid capture–based next generation sequencing (NGS). Of the 182 tumors, 8 were ALK positive by IHC. Further analysis using hybrid capture NGS analysis revealed a novel MYO18A (Exon1-40)-ALK (exon 20-29) gene fusion in one case of intraductal carcinoma. Additional genomic analyses resulted in the detection of inactivating mutations in BRAF and TP53, as well as amplifications of ERBB2 and ALK. ALK rearrangements are a rare entity in salivary gland carcinomas. We identified a potentially targetable novel ALK fusion in an intraductal carcinoma of minor salivary glands.

ALK-rearranged renal cell carcinomas in Polish population

Anaplastic lymphoma kinase (ALK) is a receptor tyrosine kinase, the activation of which is considered an important event in the pathogenesis of several neoplasms and a predictive factor for the targeted therapy with ALK inhibitors. Thus far, ALK rearrangements have been identified in 22 renal cell carcinomas in both pediatric and adult patients. We evaluated the incidence of ALK rearrangement-associated RCC in adult Central European population. An immunohistochemical evaluation of 1019 kidney tumors was performed with use of three different clones of anti-ALK antibodies. None of the tested samples showed positive staining, which suggests that the incidence of ALK rearrangement-associated renal cell carcinomas is significantly lower in the Polish population, and indicates a potential association between ethnicity and occurrence of these rare neoplasms.

ALK gene alterations in cancer: biological aspects and therapeutic implications

ALK was first reported in 1994 as a translocation in anaplastic large cell lymphoma and then described with different abnormalities in a number of tumors. Recently, a shortly accumulated biomedical research clarified the numerous biological processes underlying its ability to support cancer development, growth and progression. Advent of precision medicine has finally provided unexpected advances, leading to the development of ALK-targeting inhibitors with superior efficacy as compared with standard chemotherapy regimens, as well as the identification of resistance mechanisms and the creation of ‘next-generation’ treatments. This review summarizes the current understanding of ALK-driven cancers from the oncogenesis and mutation frequency by The Cancer Genome Atlas database through the diagnostic approach, to an updated portrait of available tyrosine kinase inhibitors, considering their effectiveness in cancer treatment, the molecular reasons of therapeutic failure, and the actual and future ways to overcome resistances.

Targeting autophagy enhances the anti-tumoral action of crizotinib in ALK-positive anaplastic large cell lymphoma

Anaplastic Lymphoma Kinase-positive Anaplastic Large Cell Lymphomas (ALK+ ALCL) occur predominantly in children and young adults. Their treatment, based on aggressive chemotherapy, is not optimal since ALCL patients can still expect a 30% 2-year relapse rate. Tumor relapses are very aggressive and their underlying mechanisms are unknown. Crizotinib is the most advanced ALK tyrosine kinase inhibitor and is already used in clinics to treat ALK-associated cancers. However, crizotinib escape mechanisms have emerged, thus preventing its use in frontline ALCL therapy. The process of autophagy has been proposed as the next target for elimination of the resistance to tyrosine kinase inhibitors. In this study, we investigated whether autophagy is activated in ALCL cells submitted to ALK inactivation (using crizotinib or ALK-targeting siRNA). Classical autophagy read-outs such as autophagosome visualization/quantification by electron microscopy and LC3-B marker turn-over assays were used to demonstrate autophagy induction and flux activation upon ALK inactivation. This was demonstrated to have a cytoprotective role on cell viability and clonogenic assays following combined ALK and autophagy inhibition. Altogether, our results suggest that co-treatment with crizotinib and chloroquine (two drugs already used in clinics) could be beneficial for ALK-positive ALCL patients.

Merkel cell carcinoma - recent advances in the biology, diagnostics and treatment

Merkel cell carcinoma (MCC) is an uncommon primary cutaneous carcinoma with neuroendocrine differentiation. Since recent discovery of MCCs strong association with Merkel cell polyomavirus (MCPyV), there has been a rapid increase in the understanding of the carcinomas genetics, molecular biology and pathogenesis. In our study, we reviewed recent advances and controversies concerning MCC histogenesis, epidemiology, diagnostic and prognostic markers. We analyzed the association of MCPyV with MCC and the possible new targets for therapy. We also examined English-based literature regarding MCC pathogenesis published between 2008 and 2013, which lead to a deeper understanding of the topic. Our study showed that the association of MCPyV strongly influences the course of MCC. Additionally, it has been shown that a immunological response to MCPyV may in the future give hope to identify new therapeutic strategies in treatment of this fatal malignancy. This article is part of a Directed Issue entitled: Rare Cancers.