p53 nuclear expression correlates with hemizygous TP53 deletion and predicts an adverse outcome for patients with relapsed/refractory multiple myeloma treated with lenalidomide.

del(17p13)(TP53) seems to be an independent poor prognostic factor in patients with relapsed/refractory multiple myeloma (MM) receiving lenalidomide. However, whether aberrant p53 nuclear expression detected by immunohistochemical analysis can be used as a surrogate marker for del(17p13)(TP53) in prognostic evaluation of lenalidomide-treated relapsed/refractory MM remains unclear. The p53 expression in myeloma cells from 88 patients was evaluated by immunohistochemical analysis, and 17p13(TP53) gene status was examined by fluorescence in situ hybridization (FISH). FISH detected hemizygous del(17p13)(TP53) in 13 (15%), and immunohistochemical analysis detected p53 nuclear expression in 11 cases (13%). del(17p13) (TP53) and p53 expression were strongly correlated (P < .0001). Furthermore, patients with aberrant p53 nuclear expression had significantly shorter progression-free and overall survival than patients without this abnormality. Our results suggest that p53 nuclear expression is associated with adverse outcome in patients with relapsed/refractory MM receiving lenalidomide-based therapy and that p53 immunohistochemical analysis may serve as a simple, rapid method to predict del(17p13)(TP53) in this patient subgroup.

Aberrant nuclear p53 expression predicts hemizygous 17p (TP53) deletion in chronic lymphocytic leukemia.

Hemizygous TP53 gene deletion is the most important adverse risk factor in chronic lymphocytic leukemia (CLL), but its relationship with p53 protein expression is unclear. We investigated 110 CLL cases and correlated nuclear p53 protein immunoreactivity with TP53 gene deletion status and other CLL-associated genetic risk factors. Fluorescence in situ hybridization detected hemizygous TP53 deletions in 15 cases (13.6%), whereas immunohistochemical analysis detected nuclear p53 protein expression in 14 (12.7%). All cases expressing nuclear p53 protein had hemizygous TP53 deletions. Hemizygous TP53 gene deletion and p53 protein expression were strongly correlated (P < .001). There was no association between p53 expression and del(13q), del(11q) or trisomy 12 in CLL cases. Our data indicate that nuclear p53 protein expression, detected by a widely available immunohistochemical method, is strongly associated with TP53 deletion and that p53 immunohistochemical analysis may be adopted as a rapid, robust diagnostic tool for risk stratification of CLL.