Assessment of MRI to estimate metastatic dissemination risk and prometastatic effects of chemotherapy.

Metastatic dissemination in breast cancer is regulated by specialized intravasation sites called "tumor microenvironment of metastasis" (TMEM) doorways, composed of a tumor cell expressing the actin-regulatory protein Mena, a perivascular macrophage, and an endothelial cell, all in stable physical contact. High TMEM doorway number is associated with an increased risk of distant metastasis in human breast cancer and mouse models of breast carcinoma. Here, we developed a novel magnetic resonance imaging (MRI) methodology, called TMEM Activity-MRI, to detect TMEM-associated vascular openings that serve as the portal of entry for cancer cell intravasation and metastatic dissemination. We demonstrate that TMEM Activity-MRI correlates with primary tumor TMEM doorway counts in both breast cancer patients and mouse models, including MMTV-PyMT and patient-derived xenograft models. In addition, TMEM Activity-MRI is reduced in mouse models upon treatment with rebastinib, a specific and potent TMEM doorway inhibitor. TMEM Activity-MRI is an assay that specifically measures TMEM-associated vascular opening (TAVO) events in the tumor microenvironment, and as such, can be utilized in mechanistic studies investigating molecular pathways of cancer cell dissemination and metastasis. Finally, we demonstrate that TMEM Activity-MRI increases upon treatment with paclitaxel in mouse models, consistent with prior observations that chemotherapy enhances TMEM doorway assembly and activity in human breast cancer. Our findings suggest that TMEM Activity-MRI is a promising precision medicine tool for localized breast cancer that could be used as a non-invasive test to determine metastatic risk and serve as an intermediate pharmacodynamic biomarker to monitor therapeutic response to agents that block TMEM doorway-mediated dissemination.

Unusual cause of cholestatic jaundice in a patient with AIDS.

A 61-year-old man with AIDS on chronic highly active antiretroviral treatment (HAART) presented with lethargy and jaundice and was found to have abnormal liver function tests (LFTs). Investigations including viral/autoimmune markers and imaging were unrevealing, except for positive Epstein-Barr virus. HAART was held, however, transaminases and total bilirubin continued to rise. The liver biopsy revealed classical Hodgkin's lymphoma (HL). HL presenting only with liver findings without lymphadenopathy is rare. Extreme cases can lead to fulminant liver failure. The bone marrow biopsy and dramatic elevation in serum ferritin were consistent with haemophagocytic lymphohistiocytosis. Finding a chemotherapy regimen was challenging given abnormal LFTs and HAART interactions. Initial chemotherapy regimen has successfully decreased LFTs; however, it was limited by pancytopenia. The patient's regimen was changed, however second regimen was complicated by neuropathy. LFTs improved and the patient was able to receive the standard care chemotherapy for HL with significant clinical, laboratory and radiological improvement.