Diagnostic accuracy of ultrasonography-guided core needle biopsy of parotid gland neoplasms: A large, single-institution experience in United Kingdom.

Salivary gland tumours present a pleomorphic and complex morphology and, apart from the most common neoplasms with well-established histopathological criteria, may create diagnostic difficulty for histopathologists. The majority of salivary gland tumours occur in the parotid gland and the use of ultrasound guided parotid biopsy (US-PB) has increased. US-PB in contrast with fine needle aspiration (FNA), which is an easy and relatively painless technique, is performed under local anaesthesia, usually by radiologists. US-PB offers some advantages over the FNA such as tumour grading and the possibility of performing immunohistochemistry. We report our experience of the diagnostic value of US-PB in a large, referral centre in the United Kingdom.

Ancestry and somatic profile predict acral melanoma origin and prognosis.

Acral melanoma, which is not ultraviolet (UV)-associated, is the most common type of melanoma in several low- and middle-income countries including Mexico. Latin American samples are significantly underrepresented in global cancer genomics studies, which directly affects patients in these regions as it is known that cancer risk and incidence may be influenced by ancestry and environmental exposures. To address this, here we characterise the genome and transcriptome of 128 acral melanoma tumours from 96 Mexican patients, a population notable because of its genetic admixture. Compared with other studies of melanoma, we found fewer frequent mutations in classical driver genes such as BRAF, NRAS or NF1. While most patients had predominantly Amerindian genetic ancestry, those with higher European ancestry had increased frequency of BRAF mutations and a lower number of structural variants. These BRAF-mutated tumours have a transcriptional profile similar to cutaneous non-volar melanocytes, suggesting that acral melanomas in these patients may arise from a distinct cell of origin compared to other tumours arising in these locations. KIT mutations were found in a subset of these tumours, and transcriptional profiling defined three expression clusters; these characteristics were associated with overall survival. We highlight novel low-frequency drivers, such as SPHKAP, which correlate with a distinct genomic profile and clinical characteristics. Our study enhances knowledge of this understudied disease and underscores the importance of including samples from diverse ancestries in cancer genomics studies.

CRISPR activation screen in mice identifies novel membrane proteins enhancing pulmonary metastatic colonisation.

Melanoma represents ~5% of all cutaneous malignancies, yet accounts for the majority of skin cancer deaths due to its propensity to metastasise. To develop new therapies, novel target molecules must to be identified and the accessibility of cell surface proteins makes them attractive targets. Using CRISPR activation technology, we screened a library of guide RNAs targeting membrane protein-encoding genes to identify cell surface molecules whose upregulation enhances the metastatic pulmonary colonisation capabilities of tumour cells in vivo. We show that upregulated expression of the cell surface protein LRRN4CL led to increased pulmonary metastases in mice. Critically, LRRN4CL expression was elevated in melanoma patient samples, with high expression levels correlating with decreased survival. Collectively, our findings uncover an unappreciated role for LRRN4CL in the outcome of melanoma patients and identifies a potential therapeutic target and biomarker.

Multi-site clonality analysis uncovers pervasive heterogeneity across melanoma metastases.

Metastatic melanoma carries a poor prognosis despite modern systemic therapies. Understanding the evolution of the disease could help inform patient management. Through whole-genome sequencing of 13 melanoma metastases sampled at autopsy from a treatment naïve patient and by leveraging the analytical power of multi-sample analyses, we reveal evidence of diversification among metastatic lineages. UV-induced mutations dominate the trunk, whereas APOBEC-associated mutations are found in the branches of the evolutionary tree. Multi-sample analyses from a further seven patients confirmed that lineage diversification was pervasive, representing an important mode of melanoma dissemination. Our analyses demonstrate that joint analysis of cancer cell fraction estimates across multiple metastases can uncover previously unrecognised levels of tumour heterogeneity and highlight the limitations of inferring heterogeneity from a single biopsy.

Excision of periocular basal cell carcinoma guided by en face frozen section.

We describe a technique for monitoring excision margins in periocular basal cell carcinoma (BCC) using en face frozen sections and report outcomes. We excised periocular BCC with 3mm margins. An outer 1mm sliver of the perimeter of the specimen was mapped and sent for evaluation by en face frozen section. The central tumour mass was processed using routine paraffin sections. A further 3mm level was excised at the site of any affected margin and the outer 1mm sliver was again evaluated by frozen section. We identified 78 patients from November 2003 to July 2009; 67 had primary tumours and 11 (14%) had recurrent BCC of which 52 (66%) were located on the lower eyelid. Growth patterns were nodular (n=34, 43%), infiltrative (n=25, 32%), micronodular (n=12, 16%), and superficial (n=7, 9%). A third of BCC with a clinically nodular appearance showed additional histological patterns including infiltrative and micronodular growth patterns. Of 30 clinically nodular carcinomas, 29 were excised completely with one level, and one required 2 levels of excision for clearance after evaluation by frozen section. Mean follow-up was 23 months (range 2-60). There was one recurrence (1%). Excision of margins guided by en face frozen section is justified by the low rates of recurrence, and it can easily be taught or imported into hospital practice. Clinically nodular BCC have subclinical extensions that can be missed on bread loaf sectioning, which makes the sampling of margins a standard for periocular BCC.