Table 1: Summary of the molecular alterations associated with familial and sporadic parathyroid tumors.

MEN1 [20, 5052]CCND1 [31, 5355]HRPT2 [13, 5658]RET [48]CaSR [49, 5961]

Germline mutationsInactivating mutations, LOHInactivating mutations, LOHActivating mutationsInactivating mutations
(Familial syndrome)(MEN1)(HPT-JT)(MEN2A)(NSHPT/FHH)

Benign
Somatic mutationsInactivating mutations, LOHActivating Inv (11) (p15; q13)Inactivating mutationsNN
Prevalence of somatic alteration20 to 30%~5%2 to 4%
Protein expression (%)Downregulation (20 to 40%)Overexpression (30 to 40%)Downregulation (ND)NDDownregulation (Up to 90%)

Malignant
Somatic mutationsInactivatingNDInactivating mutations, LOHNND
Prevalence of somatic alteration~13%ND70 to 100%
Protein expression (%)NDOverexpression (~90%)Downregulation/loss of expression
(70 to 100%)
NDDownregulation (~30%)

N: negative; ND: not determined.