Next‐generation sequencing assay in salivary gland cytology: A pilot study

Abstract

Background Preoperative diagnosis of salivary gland tumors (SGTs) by fine‐needle aspiration (FNA) cytology is challenging. Next‐generation sequencing (NGS)‐based assays for somatic mutations have a great advantage in that a large number of genes can be analyzed simultaneously. Although NGS may have an enormous diagnostic potential in cytology, to our knowledge, the significance of NGS in SGT cytology remains to be clarified. Methods In this pilot study, we retrospectively examined 32 frozen SGT samples obtained at surgery (14 malignant and 18 benign). After the stored frozen tumor tissues were thawed, aspirate samples were obtained using 22‐gauge needles and subjected to smear tumor samples and to DNA extraction for an NGS assay employing the Illumina AmpliSeq Cancer Hotspot Panel v2. The results were correlated to preoperative cytological diagnosis. Results The preoperative diagnoses obtained by FNA cytology included 23 negative lesions (no malignancy in 6 and benign tumor in 17) and nine positive lesions (suspicious for malignancy in 4 and malignancy in five), providing a sensitivity and a specificity of 9/14 (64%) and 18/18 (100%), respectively. The NGS assay detected somatic mutations in 10/14 malignant and 1/18 benign SGT cases, providing a sensitivity and a specificity of 71% and 94%, respectively. Conclusion The NGS assay may be helpful for detecting the malignant potential in SGT cases and can be used as an ancillary test for SGT cytology.

The indeterminate categories of the Milan system for reporting salivary gland cytopathology (MRSGC): A minireview

“…5 Next-generation sequencing (NGS) is a relatively new high-throughput, highly sensitive molecular technology platform with the advantage that a large number of genes can be analyzed simultaneously and that too of multiple patients in a single run. 5,24 It is a rapidly evolving field and studies have shown its effectiveness in salivary gland tumor cytology. 24,25 However, the major limitations are the high cost and requirement of robust bioinformatics to handle the analysis and interpretation of large amounts of data.…”

“…5,24 It is a rapidly evolving field and studies have shown its effectiveness in salivary gland tumor cytology. 24,25 However, the major limitations are the high cost and requirement of robust bioinformatics to handle the analysis and interpretation of large amounts of data. 26 SalvGlandDx is an all-in-one RNA-based NGS panel that detects mutations, fusions, and gene expression levels of 27 genes (including NR4A3) found in salivary gland tumors.…”

Next generation sequencing in cytology

“…Indeed, NGS yielded a sensitivity and a specificity of 71% and 94%, respectively. Notably, only 4/14 malignant cases showed no alterations, whereas only 1/18 benign lesions showed a mutation 35 . Fumagalli et al highlighted the suitability of NGS for breast cancer ( BRCA ) 1/2 gene analysis on cytological samples derived from neoplastic ascites of ovarian cancer patients.…”

“…Notably, only 4/14 malignant cases showed no alterations, whereas only 1/18 benign lesions showed a mutation. 35 Fumagalli et al highlighted the suitability of NGS for breast cancer ( BRCA ) 1/2 gene analysis on cytological samples derived from neoplastic ascites of ovarian cancer patients. In this study, NGS of cytological samples showed a success rate of 100.0%.…”

Is molecular testing of salivary gland FNA specimens ready for prime time?

“…[6][7][8][9][10] In contrast, NGS is only rarely used by cytopathologists for salivary glands aspirates. 6,8,[11][12][13][14] Moreover, the choice of the ancillary technique test depends largely on the institution's budget, available platforms, and expertise of trained staffs. However, NGS is a promising approach to facilitate the diagnosis and classification of salivary gland tumors.…”