NECTIN4 expression in sebaceous and sweat gland carcinoma

Background: Sebaceous carcinoma and sweat gland carcinoma (malignant tumours with apocrine and eccrine differentiation) are rare malignant adnexal tumours that differentiate toward sebaceous glands and eccrine and apocrine glands, respectively. Because of the rarity of these malignancies, standard treatments for advanced disease have yet to be established. The outcomes of patients with systemic metastasis remain poor, highlighting the need for novel treatment strategies. Nectin cell adhesion molecule 4 (NECTIN4) and its antibody-drug conjugate, enfortumab vedotin, have attracted attention as potential treatments for solid tumours. Objectives: To examine the potential use of NECTIN4-target therapy for sebaceous and sweat gland carcinoma. Materials & Methods: We immunohistochemically investigated NECTIN4 expression in 14 sebaceous carcinoma samples and 18 sweat gland carcinoma samples, and examined whether NECTIN4-targeted therapy could be applied to these cancers. Results: We found strong and frequent expression of NECTIN4 in both cancers. All tumours exhibited positive staining at least in a part of the lesion, and the mean H-score, a semiquantitative score ranging from 0 to 300, was 259.4 for sebaceous carcinoma and 253.1 for sweat gland carcinoma. Conclusion: Our results suggest that both sebaceous carcinoma and sweat gland carcinoma could be potentially treated with NECTIN4-targeted antibody-drug conjugates, such as enfortumab vedotin.