Mismatch repair staining is worth adding for three sarcoma types, a case series argues

The edition in brief

A US series of 39 mismatch repair-deficient sarcomas found deficiency in 1.2% of 1,531 sequenced sarcomas overall, but more often in uterine leiomyosarcoma (5.6%), undifferentiated or unclassified pleomorphic sarcoma (2.3%) and pleomorphic rhabdomyosarcoma; eight tumours were the first cancer in patients with Lynch syndrome, and some responded completely to checkpoint inhibitors. The authors propose routine MMR immunohistochemistry for these types and any sarcoma with a Lynch history; this is a proposal from a retrospective series, not a guideline. A US living guideline on early detection of oral squamous cell carcinoma limits commercial salivary adjunct tests to research, and keeps a clinical oral examination for all adults and biopsy or referral for persistent mucosal lesions. An Australian VALHUDES evaluation in 400 colposcopy attenders found self-collected vaginal swabs as sensitive as practitioner cervical samples for CIN2+ on two PCR HPV assays, with lower specificity. A Canadian laboratory used an amplicon NGS panel to call glioma copy number changes, matching FISH in a 39-case validation and cutting FISH requests by 90% in practice. A UK breast screening EQA review found expert agreement below 80% in 5.7% of cases, mostly atypical and papillary lesions. The pearl covers MLH1 loss and methylation testing.