Vessel co-option mediates resistance to anti-angiogenic therapy in liver metastases

The efficacy of angiogenesis inhibitors in cancer is limited by resistance mechanisms that are poorly understood. Notably, instead of through the induction of angiogenesis, tumor vascularization can occur through the nonangiogenic mechanism of vessel co-option. Here we show that vessel co-option is associated with a poor response to the anti-angiogenic agent bevacizumab in patients with colorectal cancer liver metastases. Moreover, we find that vessel co-option is also prevalent in human breast cancer liver metastases, a setting in which results with anti-angiogenic therapy have been disappointing. In preclinical mechanistic studies, we found that cancer cell motility mediated by the actin-related protein 2/3 complex (Arp2/3) is required for vessel co-option in liver metastases in vivo and that, in this setting, combined inhibition of angiogenesis and vessel co-option is more effective than the inhibition of angiogenesis alone. Vessel co-option is therefore a clinically relevant mechanism of resistance to anti-angiogenic therapy and combined inhibition of angiogenesis and vessel co-option might be a warranted therapeutic strategy

Nonthrombotic pulmonary embolism.

OBJECTIVE: The purpose of this essay is to highlight the clinical features and imaging findings associated with different types of nonthrombotic pulmonary embolism. CONCLUSION: Nonthrombotic pulmonary embolism is an infrequent condition with various causes that can be life-threatening pathologic conditions. The entity presents a diagnostic challenge because of the low specificity of clinical symptoms and imaging signs. Awareness of the imaging features of nonthrombotic pulmonary embolism facilitates correct diagnosis and leads to appropriate patient care

Escalating placenta invasiveness: repeated placenta accreta at the limit of viability

Shirley Greenbaum,1 Alla Khashper,2 Elad Leron,1 Eric Ohana,1 Mihai Meirovitz,1 Reli Hershkovitz,1 Offer Erez1 1Department of Obstetrics and Gynecology, 2Department of Radiology, Soroka University Medical Center, School of Medicine, Ben-Gurion University of the Negev, Be’er Sheva, Israel Abstract: Placenta percreta is an obstetric condition in which the placenta invades through the myometrium. This is the most severe form of placenta accreta and may result in spontaneous uterine rupture, a rare complication that threatens the life of both mother and fetus. In this case report, we describe a 32-year-old woman in her fourth pregnancy, diagnosed with repeated placenta accreta, which was eventually complicated by spontaneous uterine rupture at 24 weeks’ gestation. This patient had a history of abnormal placentation in prior pregnancies and previous uterine injuries. This case demonstrates a pattern of escalating placental invasiveness, and raises questions regarding the process of abnormal placentation and the manifestation of uterine rupture in scarred uteri. Keywords: placenta percreta, uterine injury, laparoscopy, dilatation and curettage, residua, cesarean section scar, spontaneous uterine ruptur