Breast carcinoma with neuroendocrine differentiation and myocardial metastases

Metastatic breast cancer simulating well-differentiated neuroendocrine neoplasms of visceral organs

A series of metastatic breast carcinoma (MBC) mimicking visceral well-differentiated neuroendocrine neoplasms has not previously been reported. We identified 5 consultation cases originally submitted as neuroendocrine neoplasms in women but that were found to be MBC on subsequent review. All 5 neoplasms demonstrated nested architecture and relatively uniform nuclei. Four patients had a known history of breast cancer (remote in 3 and concurrent in 1), but the metastases (3 liver, 1 lung) labeled for chromogranin and/or synaptophysin, prompting misdiagnosis as neuroendocrine neoplasm. In a fifth case, a liver metastasis in a patient with a known pancreatic endocrine neoplasm was originally thought to be of pancreatic origin; an occult concurrent primary breast cancer (PBC) was subsequently identified as the source. On further immunohistochemistry (IHC), all metastases evaluated were diffusely, strongly positive for estrogen receptor (5/5 cases) and GATA3 (4/4 cases). Three patients had previously received ineffective treatment for neuroendocrine carcinoma. Based on the consultation diagnosis, all 4 patients with follow-up received hormone therapy, which was effective in 3. In a separate tissue microarray cohort of paired PBCs and hematogenous MBCs, chromogranin and/or synaptophysin IHC labeling was typically negative and increased from the PBC to the MBC in only 5% of cases. In conclusion, although neuroendocrine differentiation is uncommon in breast cancer and does not commonly increase in metastases, MBC with neuroendocrine differentiation should be considered in patients with visceral neuroendocrine neoplasms of unknown primary site. Diffuse IHC labeling for estrogen receptor and GATA3 helps establish the correct diagnosis.

Neuroendocrine breast carcinoma metastatic to the liver: Report of a case and review of the literature

INTRODUCTION

Primary neuroendocrine breast carcinoma (NEBC) is a rare entity of breast cancer.

PRESENTATION OF CASE

We herein report a case of right hepatectomy for a NEBC liver metastasis.

DISCUSSION

Little is known about its evolution, bilologic behavior and optimal treatment. Its malignant potential has been addressed in few reports, with cases of metachronous metastases in diverse sites, even years following treatment of the breast primarily.

CONCLUSION

Treating this kind of cancer implies both breast and hepatic surgery.

Primary neuroendocrine breast carcinoma (NEBC) is a rare entity of breast cancer. Little is known about its evolution, biologic behavior and optimal treatment. Its malignant potential has been addressed in few reports, with cases of metachronous metastases in diverse sites, even years following treatment of the breast primarily. We herein report a case of right hepatectomy for a NEBC liver metastasis.

Rapamycin regulates stearoyl CoA desaturase 1 expression in breast cancer

Mammalian target of rapamycin (mTOR) signaling is a central regulator of protein translation, cell growth, and metabolism. Alterations of the mTOR signaling pathway are common in cancer, making mTOR a promising therapeutic target. In clinical trials, rapamycin analogs have shown modest response rates for most cancer types, including breast cancer. Therefore, there is an urgent need to better understand the mechanism of action of rapamycin to improve patient selection and to monitor pathway inhibition. To identify novel pharmacodynamic markers of rapamycin activity, we carried out transcriptional profiling of total and polysome-associated RNA in three breast cancer cell lines representing different subtypes. In all three cell lines, we found that rapamycin significantly decreased polysome-associated mRNA for stearoyl-CoA desaturase 1 (SCD1), the rate-limiting enzyme in monounsaturated fatty acid synthesis. Activators of mTOR increased SCD1 protein expression, whereas rapamycin, LY294002, and BEZ235 decreased SCD1 protein expression. Rapamycin decreased total SCD1 RNA expression without inducing a significant decline in its relative polysomal recruitment (polysome/total ratio). Rapamycin did not alter SCD1 mRNA stability. Instead, rapamycin inhibited SCD1 promoter activity and decreased expression of mature transcription factor sterol regulatory element binding protein 1 (SREBP1). Eukaryotic initiation factor 4E (eIF4E) small interfering RNA (siRNA) decreased both SCD1 and SREBP1 expression, suggesting that SCD1 may be regulated through the mTOR/eIF4E-binding protein 1 axis. Furthermore, SCD1 siRNA knockdown inhibited breast cancer cell growth, whereas overexpression increased growth. Taken together these findings show that rapamycin decreases SCD1 expression, establishing an important link between cell signaling and cancer cell fatty acid synthesis and growth.