A region on the long arm of chromosome 16 is frequently deleted in metastatic node-negative breast cancer.

The aim of the present study was to define which region of chromosome 16q is most relevant for evaluation of the risk of metastatic recurrence in human breast cancer cases that are lymph node-negative at the time of diagnosis. For this purpose we examined 36 cases of sporadic breast carcinoma subdivided into 3 groups: the first group: no metastatic progression after an average follow-up time of 15 years; including patients with and without lymph node metastases at the time of diagnosis; the second group: N+ (node-positive) patients only, developed metastasis in five years from surgical excision. The last group was composed of patients who developed metastasis but were N0 (node-negative) at diagnosis. A statistically significant association was found between LOH (loss of heterozygosity) at 16q and metastatic progression of the neoplastic disease. 16q LOH was identified as a new independent molecular marker of progression for tumor N0 at diagnosis.