The method of cytological examination by fine needle aspiration biopsy (FNAB) was developed clinically in breast cancer and enabled us to prepare cancer cell nuclei for the detection of p53 gene mutation. In the expectation that this method would improve the prediction of postoperative prognosis, the observation of 10 year survival for breast cancer patients with p53 gene mutations was done. The DNA of the aspirated cells was examined preoperatively for gene alterations in 53 patients with breast cancer. The p53 protein accumulation, DNA ploidy pattern, estrogen receptor (ER) , and clinicopathological factors were examined postoperatively The postoperative follow up was conducted over 10 years and evaluated the status of p53 gene mutation. In 26 patients (49.1%) , 29 p53 gene mutations were shown. p53 protein accumulations and DNA aneuploidy patterns were detected in 33 (62.3%) and 42 (79.2%) cases, respectively, and both significantly correlated with p53 gene mutations. With regard to the postoperative prognosis, in over 10 years of observation, the patients who showed p53 mutations had a significantly worse prognosis in both disease free survival and overall survival than those showing negative p53 mutation. A similar tendency was also seen in patients with histologic grade 3. Using FNAB, the usefulness of the preoperative detection of p53 gene mutation was revealed, suggesting its clinical benefits for predicting a patient\u27s prognosis
