<i>TP53</i> Abnormalities and MMR Preservation in 5 Cases of Proliferating Trichilemmal Tumours

• Main Authors: Raquel Martín-Sanz, José María Sayagués, Pilar García-Cano, Mikel Azcue-Mayorga, María del Carmen Parra-Pérez, María Ángeles Pacios-Pacios, Enric Piqué-Durán, Jorge Feito
• Format: Article
• Language: English
• Published: MDPI AG 2021-05-01
• Series: Dermatopathology
• Subjects: trichilemmal cyst; proliferating trichilemmal tumor; MMR; <i>TP53</i>; p53
• Online Access: https://www.mdpi.com/2296-3529/8/2/21

Proliferating trichilemmal tumours (PTT) are defined by a benign squamous cell proliferation inside a trichilemmal cystic (TC) cavity. A possible explanation of this proliferative phenomenon within the cyst may be molecular alterations in genes associated to cell proliferation, which can be induced by ultraviolet radiation. Among other genes, alterations on <i>TP53</i> and DNA mismatch repair proteins (MMR) may be involved in the cellular proliferation observed in PTT. Based on this assumption, but also taking into account the close relationship between the sebaceous ducts and the external root sheath where TC develop, a MMR, a p53 expression assessment and a <i>TP53</i> study were performed in a series of 5 PTT cases, including a giant one. We failed to demonstrate a MMR disorder on studied PTT, but we agree with previous results suggesting increased p53 expression in these tumours, particularly in proliferative areas. <i>TP53</i> alteration was confirmed with FISH technique, demonstrating <i>TP53</i> deletion in most cells.