Expressions of the CIP/KIP family of CDK inhibitor proteins in primary intestinal large B-cell lymphomas: Correlation with clinical outcomes

Immumohistochemistry was performed for p21, p27, p57 and p53 on paraffin-embedded tissue sections from 25 patients who had surgically resected intestinal lymphomas. It was then correlated with the patients' clinical course in an attempt to determine the expression patterns and clinical significance of the CIP/KIP family of cyclin-dependent kinase inhibitors in primary intestinal large B-cell lymphomas. p21 immunostaining was positive in 11 cases (44%) and p27 was positive in 8 cases (32%). All cases were p57-negative. p53 immunostaining was positive in 14 cases (56%) and negative in 11 cases (44%). With respect to the relationship between p21 and p53, seven cases were p53(+)/p21(-), seven cases were p53(+)/p21(+), seven cases were p53(-)/p21(-), and four cases were p53(-)/p21(+). The expression patterns of p21 and p53 did not influence the patient's clinical outcome. However, p27-positive cases had a much higher percentage of patients sustaining a continuous complete remission state (8/8, 100%) as compared to p27-negative cases (10/17, 59%), although this difference was not statistically significant (p = 0.057). These results suggest that p27 immunoreactivity may be associated with a better clinical outcome. However, further study with larger series are planned to determine the clinical significance of p27 overexpression in primary intestinal large B-cell lymphomas.