TdT expression in germ cell tumours: A possible immunohistochemical cross-reaction and diagnostic pitfall

Marta Jaconi, Fulvio Magni, Francesca Raimondo, Maurilio Ponzoni, Clizia Chinello, Andrew Smith, Isabella Piga, Nicola Fusco, Camillo Di Bella, Fabio Pagni

Research output: Contribution to journalArticlepeer-review


Aims: Very recent papers proposed a possible role for the expression of terminal deoxynucleotidyl transferase (TdT) in the tumourigenesis of gonadal and extragonadal germ cell-derived tumours (GCTs). Our multicentric study evaluated the magnitude of the immunoreactivity for TdT in GCTs, encompassing seminoma, dysgerminoma, mature teratoma and mixed GCTs. Methods and results: The histological series was stained with both monoclonal and polyclonal antibodies, yielding a positivity of 80% of cases with well-defined nuclear reactivity. A significant difference in staining intensity between monoclonal and polyclonal antibodies was observed (p=0.005). However, exploiting western blot and more innovative proteomic approaches, no clear-cut evidence of the TdT protein was observed in the neoplastic tissues of the series. Conclusions: Alternatively to the pathogenetic link between TdT expression and GCTs tumourigenesis, we hypothesised the occurrence of a spurious immunohistochemical nuclear cross-reaction, a well-known phenomenon with important implications and a possible source of diagnostic pitfalls in routine practice for pathologists.

Original languageEnglish
Pages (from-to)536-541
JournalJournal of Clinical Pathology
Issue number8
Publication statusPublished - Jan 1 2019


  • differential diagnosis
  • genital system
  • germinal cell tumor
  • haematopoietic
  • seminoma
  • tdt
  • terminal deoxynucleotidyl transferase

ASJC Scopus subject areas

  • Pathology and Forensic Medicine


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