[Neuroendocrine expression markers in triple-negative, luminal-A, luminal-B and HER2neu breast cancer].

BACKGROUND

Primary breast tumors with neuroendocrine (NE) differentiation are a heterogeneous tumor group with diversity of biological behavior, with poorly defined prevalence and prognosis.

OBJECTIVE

To evaluate the chromogranin, synaptophysin, CD56, INSM1 markers expression prevalence and the association between NE differentiation and tumor molecular type.

MATERIAL AND METHODS

Observational, cross-sectional study which included 110 breast tissue samples with primary invasive carcinoma. Immunohistochemistry was performed for chromogranin, synaptophysin, CD56 and INMS1 markers. NE differentiation was considered with 10-90% positive cells, and NE tumor with > 90% positive cells.

RESULTS

26.3% showed neuroendocrine differentiation. Out of these, 48.2% were luminal-A type, 24.1% luminal-B, 11.5% HER2neu, 17.2% triple-negative; 1.8% were NE tumors. Tumors were marker positive, and out of these to chromogranin in 24.5%, synaptophysin in 28.2%, CD56 in 2.7%, INSM1 in 16.4%. Synaptophysin was expressed in 17.3% luminal-A type, 6.4% luminal-B, 0.9% HER2neu, 3.6% triple-negative. NE differentiation showed association with synaptophysin expression (r = 0.586, p = 0.0001).

CONCLUSION

The NE differentiation prevalence was 26.3% in primary invasive breast cancers, with luminal-A molecular type predominance.