The aim of our study was to investigate the correlation of the proliferative activity of pituitary neoplasms with clinical characteristics and recurrences. Tumor specimens were obtained from 44 consecutive patients with pituitary macroadenomas who underwent surgery between July 1998 and August 2003. Specimens were immediately fixed in 10% buffered formalin and then embedded in paraffin. The Ki-67 antigen was assessed by immumohistochemical analysis using the monoclonal antibody. We investigated the correlation of the Ki-67 labeling index with the following clinical and radiological characteristics: sex, age, presence or absence visual field defect, tumor classification, maximal tumor diameter, Hardy's classification, type of tumor, invasiveness, and recurrence. Our study suggests that the clinical characteristics such as visual field defect and recurrence are correlated with the high Ki-67 labeling index. No statistical differences were observed in the Ki-67 labeling index in relation to the following characteristics: sex, age, tumor classification, maximal tumor diameter, Hardy's classification, type of tumor, and invasiveness into the sphenoid sinus or cavernous sinus.
Adenoma/metabolism/*pathology/radiography ; Adult ; Aged ; Comparative Study ; Female ; Humans ; Immunohistochemistry ; Ki-67 Antigen/*analysis ; Male ; Middle Aged ; Neoplasm Recurrence, Local ; Pituitary Neoplasms/metabolism/*pathology/radiography

Several molecular and genetic changes have been found in pituitary adenomas. We looked for correlations between these changes and the degree of invasiveness of the tumors. The invasiveness of 11 pituitary adenomas was graded by Hardy classification. We examined the retinoblastoma gene (RB1.20 on chromosome 13q) and the region around the MEN1 locus (chromosome 11q13.1-5) for loss of heterozygosity. Also examined are p53 mutations using single strain conformation polymorphism, p53 protein overexpression using immuno cytochemistry, homozygous deletions of p15 and p16 by polymerase chain reaction, and cellular proliferative activity using MIB-1 antibody. Six tumors (54.5%) had an LOH at either RB1.20 or the MEN1 locus. LOHs were found more frequently in Grade 4 and stage E tumors (72% and 67%) than in Grade 3 and stage D tumors (25% and 40%). However, no mutation or overexpression of p53 was found. No homozygous deletions of p15 or p16 were identified. The cell proliferative index ranged from 0 to 3%. LOH at 11q13 and 13q may be valuable in predicting the invasiveness of pituitary adenomas.
Adenoma/*genetics/*pathology/physiopathology/radiography ; Adult ; Aged ; Aged, 80 and over ; Cell Cycle Proteins/genetics ; Cell Transformation, Neoplastic ; Chromosomes, Human, Pair 11 ; Chromosomes, Human, Pair 13 ; Female ; *Genes, Retinoblastoma ; Genes, Tumor Suppressor ; Genes, p53 ; Human ; Loss of Heterozygosity ; Male ; Middle Age ; Mutation ; Neoplasm Invasiveness ; Neoplasm Proteins/*genetics ; Pituitary Neoplasms/*genetics/*pathology/physiopathology/radiography ; Polymorphism, Single-Stranded Conformational ; Protein p16/genetics ; Protein p53/genetics/metabolism