[The expression of p53 protein in patients with multiple myeloma].

INTRODUCTION

Although mutations of p53 are one of the most often acquired genetic changes in malignant tumors, these mutations are rare events in patients with newly diagnosed multiple myeloma (MM). Moreover, there are a few literature data about clinical significance of p53 overexpression in multiple myeloma.

OBJECTIVE

The aim of our study was to evaluate the clinical significance of p53 immunoexpression in multiple myeloma.

METHOD

A total of 58 patients with newly diagnosed MM (26 females and 32 males, mean age 62 years) were enrolled in the study. The diagnosis of MM was made according to criteria of Chronic Leukemia-Myeloma Task Force. Clinical staging was done according to Durie and Salmon classification (4 patients had disease stage 1, 15 patients stage II and 39 patients stage III). The histological grade and histological stage were determined according to predominant plasma cell morphology and volume of myeloma infiltration, respectively. Standard immunohistochemical analysis with p53 antibody in B5-fixed and paraffin-embedded bone marrow specimens was used to evaluate the expression of p53 in myeloma cells. The specimens were considered positive when 25% of plasma cells exhibited clear nuclear positivity.

RESULTS

Out of 58 patients, p53 expression was detected in 9 (15.52%). No significant correlation was found between p53 expression and clinical stage (I+II vs. III), beta2-microglobulin level (< or =6 mg/L vs. > 6 mg/L), histological grade (I vs. II+III), histological stage (<20% vs. 21-50% vs. >50%) and the extent of osteolytic lesions (< or =3 vs. >3 lesions). Median survival of patients with p53 immunoreactivity in =>5% of plasma cells was 10 months, whilst median survival of patients with p53 immunoreactivity in <5% of plasma cells was 36 months. However, such difference was not significant (p = 0.2).

CONCLUSION

The frequency of p53 immunoexpression in our group of newly diagnosed MM was relatively low. Although p53 immunoexpression was not associated with clinical and histological features of more aggressive disease, or with shorter survival, further investigations of larger group of patients will lead to final conclusions.