Mutation hotspots are either solitary amino acid residues or stretches of amino acids that show elevated mutation frequency in cancer-related genes, but their prevalence and biological relevance are not completely understood. Here, we developed a Smith-Waterman algorithm-based mutation hotspot discovery method, MutClustSW, to identify mutation hotspots of either single or clustered amino acid residues. We identified 181 missense mutation hotspots from COSMIC and TCGA mutation databases. In addition to 77 single amino acid residue hotspots (42.5%) including well-known mutation hotspots such as IDH1 (p.R132) and BRAF (p.V600), we identified 104 mutation hotspots (57.5%) as clusters or stretches of multiple amino acids, and the hotspots on MUC2, EPPK1, KMT2C, and TP53 were larger than 50 amino acids. Twelve of 27 nonsense mutation hotspots (44.4%) were observed in four cancer-related genes, TP53, ARID1A, CDKN2A, and PTEN, suggesting that truncating mutations on some tumor suppressor genes are not randomly distributed as previously assumed. We also show that hotspot mutations have higher mutation allele frequency than non-hotspots, and the hotspot information can be used to prioritize the cancer drivers. Together, the proposed algorithm and the mutation hotspot information can serve as valuable resources in the selection of functional driver mutations and associated genes.

Background: Posterior neck lipomatosis, commonly referred to as a buffalo hump, is characterized by abnormal accumulation of adipose and fibrofatty tissue in the dorsocervical region, leading to aesthetic deformity and functional discomfort. Ultrasound-assisted liposuction (UAL) has been widely used as a minimally invasive treatment option, particularly for fibrous adipose tissue; however, surgical outcomes may vary depending on regional anatomical characteristics. Methods: This retrospective observational study included five patients with idiopathic posterior neck lipomatosis who underwent UAL using a superwet infiltration technique. Liposuction was performed through three access ports, with initial deep-plane debulking followed by contour refinement. Postoperative outcomes were assessed based on clinical examination, standardized photographic documentation, and patient-reported satisfaction during follow-up. Results: The mean follow-up duration was 8.2 months (range, 7–10 months). All patients demonstrated visible improvement in dorsocervical contour following UAL. The mean volume of tumescent infiltration was 176 mL (range, 100–250 mL), and the mean lipoaspirate volume was 178 mL (range, 110–280 mL). Four patients achieved satisfactory contour improvement and reported high satisfaction. One patient exhibited residual dorsocervical prominence consistent with relative undercorrection, despite adequate aspiration volume and ultrasonic application. No major perioperative or postoperative complications were observed. Conclusions: Ultrasound-assisted liposuction appeared to provide favorable short-term contour improvement in this small series of idiopathic posterior neck lipomatosis. However, dense fibrous septation and deep fascial tethering in the dorsocervical region may limit complete correction in selected patients, even when aspiration volume and ultrasonic application are considered adequate. Recognition of these anatomical constraints may help refine surgical planning, improve preoperative counseling, and guide expectations regarding residual fullness.