Osteopontin and p53 expression are associated with tumor progression in a case of synchronous, bilateral, invasive mammary carcinomas.

OBJECTIVE: To examine the association between expression of osteopontin (OPN), p53, other molecular markers (Ki-67, c-erb B2, and estrogen receptor protein) and tumor progression in a case of synchronous, bilateral, invasive mammary carcinomas of the same histology.
DESIGN: Immunohistochemistry was performed on formalin-fixed, paraffin-embedded tissue sections. Plasma OPN level was determined by a quantitative antigen capture assay.
SETTING: The patient was seen, treated, and followed up for a period of 5 years at the London Regional Cancer Centre, Ontario, Canada. PATIENT: A 60-year-old woman presented with bilateral infiltrating mammary carcinomas of the same histologic type and grade. Bilateral mastectomy and axillary node dissection showed involvement of 3 of 12 right axillary and 0 of 11 left axillary lymph nodes. She later developed a right chest wall recurrence, followed by widespread metastatic disease to the skull, liver, and left femur.
RESULTS: The primary tumor of the right breast was OPN- and p53-positive, whereas the tumor of the left breast was negative for both markers. The development of right axillary lymph node metastases, chest wall recurrence, and distant metastases was associated in all instances with an immunohistochemical profile of high level expression of OPN and p53. Plasma assay for OPN at the time of last admission showed a markedly elevated OPN level.
CONCLUSIONS: Increased p53 expression was found to be associated with increased tumor aggressiveness. The association of increased OPN expression with increased malignancy in breast cancer is a novel finding and raises the possibility of a role for OPN in tumor progression, as well as the potential for this marker in predicting clinical aggressiveness.