AIMS: Alterations of cell-cycle regulatory molecules in tumorigenesis may predict the biological behaviour of neoplasms and greatly contribute to their proper classification. Since the behaviour of proliferating trichilemmal tumour (PTT) is controversial, we decided to explore the possible significance of altered p53 and p27Kip1 immunohistochemical expression patterns in PTT. METHODS AND RESULTS: We evaluated the percentage and distribution of positive tumour cells and compared the results with those obtained from usual trichilemmal cysts (TC) and squamous cell carcinomas with trichilemmal differentiation (SCCT). PTT showed p53 immunoreactivity (50.4 +/- 29.6, mean +/- standard deviation) that was not statistically different from that seen in SCCT (75.2 +/- 36.3). On the other hand, p53 immunostaining was virtually absent in TC cases (positivity for p53 was observed in only one instance in < 1% of cells). As for p27Kip1, the mean percentage of positive cells in PTT (82.7 +/- 9.9) was slightly lower than in TC (90.6 +/- 4.6) but significantly higher than in SCCT (53.4 +/- 30). CONCLUSIONS: The similar p53 immunoreactivity in both PTT and SCCT favour the interpretation of the former as carcinoma, albeit one whose behaviour would be tempered by the well-known regulatory effect exerted by p27Kip1 on the cell cycle.
AIMS: Alterations of cell-cycle regulatory molecules in tumorigenesis may predict the biological behaviour of neoplasms and greatly contribute to their proper classification. Since the behaviour of proliferating trichilemmal tumour (PTT) is controversial, we decided to explore the possible significance of altered p53 and p27Kip1 immunohistochemical expression patterns in PTT. METHODS AND RESULTS: We evaluated the percentage and distribution of positive tumour cells and compared the results with those obtained from usual trichilemmal cysts (TC) and squamous cell carcinomas with trichilemmal differentiation (SCCT). PTT showed p53 immunoreactivity (50.4 +/- 29.6, mean +/- standard deviation) that was not statistically different from that seen in SCCT (75.2 +/- 36.3). On the other hand, p53 immunostaining was virtually absent in TC cases (positivity for p53 was observed in only one instance in < 1% of cells). As for p27Kip1, the mean percentage of positive cells in PTT (82.7 +/- 9.9) was slightly lower than in TC (90.6 +/- 4.6) but significantly higher than in SCCT (53.4 +/- 30). CONCLUSIONS: The similar p53 immunoreactivity in both PTT and SCCT favour the interpretation of the former as carcinoma, albeit one whose behaviour would be tempered by the well-known regulatory effect exerted by p27Kip1 on the cell cycle.
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 Journal: Dermatopathology (Basel) Date: 2021-05-25