GPNMB is sensitive for uterine PEComa but not specific enough to use alone

The edition in brief

A study of 115 uterine mesenchymal tumours found that GPNMB immunostaining was diffusely moderate to strong in all nine PEComas, but also in 9 of 19 leiomyosarcomas, 2 of 5 undifferentiated uterine sarcomas, 2 of 3 inflammatory myofibroblastic tumours and 1 of 18 low-grade endometrial stromal sarcomas, so it should be interpreted with morphology and a wider panel. In 203 patients with early triple-negative breast cancer given neoadjuvant chemotherapy plus pembrolizumab, pathological complete response was 63.1% and was associated with higher grade, more tumour-infiltrating lymphocytes and higher Ki-67, while residual disease patterns and nodal responses were heterogeneous. A meta-analysis of 30 studies found Franseen needles gave higher odds of adequate EUS samples than standard needles (OR 2.83) and of optimal histological cores (OR 5.02), with small-study effects. The Testicular Sex Cord-Stromal Tumour group proposed a hierarchical classification of these tumours in July. The pearl restates that immunostains are read as part of a panel with morphology and controls.