Timely topic: anaplastic lymphoma kinase (ALK) spreads its influence

Synthesis and preliminary PET imaging of 11C and 18F isotopologues of the ROS1/ALK inhibitor lorlatinib

Lorlatinib (PF-06463922) is a next-generation small-molecule inhibitor of the orphan receptor tyrosine kinase c-ros oncogene 1 (ROS1), which has a kinase domain that is physiologically related to anaplastic lymphoma kinase (ALK), and is undergoing Phase I/II clinical trial investigations for non-small cell lung cancers. An early goal is to measure the concentrations of this drug in brain tumour lesions of lung cancer patients, as penetration of the blood–brain barrier is important for optimal therapeutic outcomes. Here we prepare both ¹¹C- and ¹⁸F-isotopologues of lorlatinib to determine the biodistribution and whole-body dosimetry assessments by positron emission tomography (PET). Non-traditional radiolabelling strategies are employed to enable an automated multistep ¹¹C-labelling process and an iodonium ylide-based radiofluorination. Carbon-11-labelled lorlatinib is routinely prepared with good radiochemical yields and shows reasonable tumour uptake in rodents. PET imaging in non-human primates confirms that this radiotracer has high brain permeability.

Lorlatinib—a ROS1/ALK inhibitor—is currently undergoing clinical trials for the treatment of non-small cell lung cancers. Here the authors develop synthetic routes to ¹¹C- and ¹⁸F-labelled lorlatinib, with subsequent PET imaging showing good blood brain barrier permeability in non-human primates.

Anaplastic large cell lymphoma (ALCL) and breast implants: breaking down the evidence

Systemic anaplastic large cell lymphoma (ALCL) is a distinct disease classification provisionally sub-divided into ALCL, Anaplastic Lymphoma Kinase (ALK)(+) and ALCL, ALK(-) entities. More recently, another category of ALCL has been increasingly reported in the literature and is associated with the presence of breast implants. A comprehensive review of the 71 reported cases of breast implant associated ALCL (iALCL) is presented indicating the apparent risk factors and main characteristics of this rare cancer. The average patient is 50 years of age and most cases present in the capsule surrounding the implant as part of the periprosthetic fluid or the capsule itself on average at 10 years post-surgery suggesting that iALCL is a late complication. The absolute risk is low ranging from 1:500,000 to 1:3,000,000 patients with breast implants per year. The majority of cases are ALK-negative, yet are associated with silicone-coated implants suggestive of the mechanism of tumorigenesis which is discussed in relation to chronic inflammation, immunogenicity of the implants and sub-clinical infection. In particular, capsulotomy alone seems to be sufficient for the treatment of many cases suggesting the implants provide the biological stimulus whereas others require further treatment including chemo- and radiotherapy although reported cases remain too low to recommend a therapeutic approach. However, CD30-based therapeutics might be a future option.

Role of molecular studies in the classification of lymphoma

The classification of lymphomas has historically lacked both precision and accuracy, potentially compromising both optimal diagnosis and therapy. The genetic characterization of key oncogenic events and the advent of expression profiling have afforded the opportunity to understand, diagnose and treat these diseases in a much more rational and targeted manner. As exciting as these new and testable data are, it is also worth noting that molecular genetic analysis of the tumor in isolation will not be the sole arbiter of patient outcome. It is likely that we will remain reliant on traditional and sometimes subjective technologies, albeit probably to a lesser degree, with molecular studies significantly complementing, but certainly not replacing, microscopic, immunophenotypic and cytogenetic approaches. Furthermore, we will perhaps need to extend genotyping to the tumor milieu (the patient) in order to molecularly dissect drug metabolic pathways and the immune response.

Diffuse large B-cell lymphoma: a heterogeneous group of non-Hodgkin lymphomas comprising several distinct clinicopathological entities

Diffuse large B-cell lymphoma (DLBCL) as defined by the World Health Organization (WHO) classification is clinically, morphologically and genetically a heterogeneous group of malignant proliferations of large lymphoid B cells. Over the last 6 years, several studies have been published improving our understanding of these lymphomas. These studies analyzed DLBCL by their gene expression profile, provided further information on some of the variants of DLBCL listed in the WHO classification and stressed the impact of the site of origin of these tumors. This review summarizes these recent data and explores their impact on the recognition of new clinicopathological lymphoma entities.

An approach to the surgical pathology of tumours and tumour-like conditions of the liver

Hepatic masses are increasingly being found, often as a result of more frequent and sophisticated imaging. Lesions can be detected during screening for primary and metastatic tumours, or as an incidental finding. Although some have distinctive radiological appearances allowing for a confident diagnosis, histological assessment of biopsy and resection specimens remains the cornerstone for the correct identification of many lesions. This broadsheet describes the distinctive features of common and uncommon hepatic tumours and outlines diagnostic problems and pitfalls, particularly for the benign and malignant tumours of hepatocytes and bile ducts. Tumour-like lesions that mimic malignancy are also discussed. Finally, an approach to the assessment of biopsies from probable metastatic tumours is presented, as this is one of the most common indications for liver mass biopsy for the practising pathologist.

Intravascular inflammatory myofibroblastic tumors in infancy

Inflammatory myofibroblastic tumor (IMT), previously described as inflammatory pseudotumor, can occur at any age but is a recognized soft tissue tumor of childhood. Less than 10 previous cases have been described of IMT affecting the heart, in patients ranging from 5 months to 17 years of age. We present three unusual, but similar, cases of IMT in infants, which were all predominantly intravascular in location, one of which was associated with death due to angiodestructive lesions of the coronary and cerebral arteries. These cases demonstrate an apparently distinct phenotype, with a predominant intravascular location of the tumor. Furthermore, this series highlights the difficulty in categorizing such lesions as benign versus malignant on histological grounds alone. IMT should be considered in the differential diagnosis of unusual pediatric intravascular spindle cell lesions.