Duodenal Metastasis in Triple-Negative Invasive Ductal Breast Carcinoma With Negative Mammography: A Case Report and Review of the Literature.

Breast cancer metastasis to the gastrointestinal tract is uncommon, and duodenal involvement is exceptionally rare. Those cases that do metastasize are reported to be lobular, with ductal carcinomas comprising only a small percentage of reported cases. Furthermore, these invasive carcinomas are typically estrogen receptor-, progesterone receptor-positive ± human epidermal growth factor receptor 2 malignancies. We present a unique case of a patient with duodenal metastasis as the first sign of metastatic breast cancer. The rarity of this case is highlighted by the fact that the patient had no known breast malignancy, and pathological findings revealed triple-negative invasive ductal carcinoma consistent with primary breast cancer. Diagnostic mammogram and ultrasound were negative for any lesions.

Identification of a mammalian-type phosphatidylglycerophosphate phosphatase in the Eubacterium Rhodopirellula baltica.

Cardiolipin is a glycerophospholipid found predominantly in the mitochondrial membranes of eukaryotes and in bacterial membranes. Cardiolipin interacts with protein complexes and plays pivotal roles in cellular energy metabolism, membrane dynamics, and stress responses. We recently identified the mitochondrial phosphatase, PTPMT1, as the enzyme that converts phosphatidylglycerolphosphate (PGP) to phosphatidylglycerol, a critical step in the de novo biosynthesis of cardiolipin. Upon examination of PTPMT1 evolutionary distribution, we found a PTPMT1-like phosphatase in the bacterium Rhodopirellula baltica. The purified recombinant enzyme dephosphorylated PGP in vitro. Moreover, its expression restored cardiolipin deficiency and reversed growth impairment in a Saccharomyces cerevisiae mutant lacking the yeast PGP phosphatase, suggesting that it is a bona fide PTPMT1 ortholog. When ectopically expressed, this bacterial PGP phosphatase was localized in the mitochondria of yeast and mammalian cells. Together, our results demonstrate the conservation of function between bacterial and mammalian PTPMT1 orthologs.