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XXII CONGRESSO NAZIONALE S.I.FI.PA.C. HRPT2 mutations, Parafibromin and PGP 9,5 expression in sporadic parathyroid carcinoma. Iacobone M., Ciarleglio F.A., Viel G., Bottussi M., Tropea S., Citton M., Kertusha X., Frego M., Favia G. Endocrine Surgery Unit University of Padua, Italy.
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XXII CONGRESSO NAZIONALE S.I.FI.PA.C HRPT2 mutations, Parafibromin and PGP 9,5 expression in sporadic parathyroid carcinoma Iacobone M., Ciarleglio F.A., Viel G., Bottussi M., Tropea S., Citton M., Kertusha X., Frego M., Favia G. Endocrine Surgery Unit University of Padua, Italy Sabato 4 aprile 2009
Histopathological diagnosis of malignancy Parathyroid Carcinoma (1%) • Uniform growth + dense fibrous trabeculae • Atypical mitoses • Capsular and vascular invasion Schantz & Castleman 1973
Parathyroid Carcinoma Challenging diagnosis Extracapsular and vascular invasion LOCAL RECURRENCES DISTANT METASTASES
Parathyroid Carcinoma • Additional Molecular Markers • HRPT2 mutations (Howell, Shattuck 2003) • PGP 9.5 expression (Howell 2009)
Inactivating Mutations HRPT2 Cromosome 1q31.2 PARAFIBROMIN Parathyroid Carcinoma CELLULAR PROLIFERATION
Activation of UCHL-1 Overexpression of PGP 9.5 Lung, Pancreas, Colon and Parathyroid Carcinoma
AIM Verify the diagnostic role in Parathryoid Carcinoma of: • HRPT2 somatic mutations • Parafibromin Expression • PGP 9.5 Expression
Matherials and Methods • 10 normal parathyroids • 20 sporadic parathyroid adenomas • 3 sporadic parathyroid carcinomas • Germ-line and somatic HRPT2 mutations • Parafibromin immunohistochemistry • PGP 9.5 immunohistochemistry
Results (1) HRPT2 mutations c.85G>T; Glu29X
Results (3) PARAFIBROMIN EXPRESSION (Immunohistochemistry) +++: >90% -: <10%
Results (4) Parafibromin expression (immunohistochemistry) PARATHYROID ADENOMA Positive nuclear staining (>90%) PARATHYROID CARCINOMA Variable nuclear staining (60%) PARATHYROID CARCINOMA Absence of nuclear staining (<10%) PARATHYROID CARCINOMA Variable nuclear staining (70%)
Results (5) PGP 9.5 EXPRESSION (Immunohistochemistry) +++: >90% -: <10%
Results (6) PGP 9.5 expression (immunohistochemistry) PARATHYROID ADENOMA Weak staining (-) PARATHYROID CARCINOMA Variable staining (+/-) 70% PARATHYROID CARCINOMA Variable staining (+/-) 60% PARATHYROID CARCINOMA Strongly Positive staining (++)
Results (7) +++: >90% -: <10%
Conclusions • Loss of Parafibromin is an useful tool for PC diagnosis (High Specificity) • HRPT2 mutations are not involved in all PC • The Negative Predictive Value of Loss of Parafibromin may be inadequate • PGP 9.5 is strongly expressed in PC • In challenging cases PGP 9.5 may be useful, but further studies are necessary