Hepatic regeneration in a rat model is impaired by chemotherapy agents used in metastatic colorectal cancer.

PURPOSE: Administering Oxaliplatin prior to resection of colorectal liver metastases often induces a Sinusoidal Obstruction Syndrome (SOS), which can affect postoperative patient outcome. Bevacizumab (Anti-VEGF-A) can decrease the severity of SOS and the associated risk of postoperative liver failure. We investigated the impact of both Oxaliplatin (Oxali) and Bevacizumab on liver regeneration in a rat model. MATERIAL AND METHODS: Male Wistar rats underwent a 70% partial hepatectomy (PH) 3 days after a 2 ml intraperitoneal injection of either saline (controls, n = 17), or Oxaliplatin 10, 20 or 50 mg/kg, 5-Fluorouracil 100 mg/kg (5-FU) and Bevacizumab 5 or 10 mg/kg in various combinations (total 98 rats, 11 groups, n = 5-18/group). Liver regeneration was assessed by remnant liver weight recovery and cell proliferation by immunodetection of BrDU incorporation (days 1, 2, 3, 7). Hepatic mRNA expression levels of VEGF-A and of its 2 receptors (Flt-1 and KDR) were quantified by PCR technique. RESULTS: Liver regeneration was impaired for 3 days post PH by Oxali 20 alone and Oxali 10 + 5-FU, without any rescue effect by neither Bevacizumab 5 nor 10 mg/kg. Unlike in humans, there were no sinusoidal changes. VEGF-A mRNA expression and receptor 2 (KDR) expressions decreased 24 h post PH in a similar fashion in controls, Oxali 20 and Oxali 10 + 5-FU groups. All groups had recovered over 60% of their liver weight by day 7. CONCLUSION: Oxaliplatin causes early hepatocyte proliferation impairment post PH, unaffected by Bevacizumab and unexplained by changes in VEGF-A signalling in a Wistar rat model.

[Early loss of heterozygosity on chromosome arm 16q in flat epithelial atypia of the breast. Detection by microsatellite analyses]. / Früher Verlust der Heterozygotie auf Chromosomenarm 16q in flachen epithelialen Atypien der Brust. Detektion durch Mikrosatellitenanalysen.

With the improvement of breast carcinoma screening, pre-malignant cell lesions such as flat epithelial atypia (FEA) are detected more frequently. Several studies have demonstrated that FEA show features of a ductal neoplasia, but is it really a precursor lesion? We have started a comparative genetic analysis of a panel of nine microsatellite markers on six different chromosomal regions to investigate whether FEAs show the same characteristic genetic alterations as ductal carcinomas in situ (DCISs) and invasive carcinoma of the breast. FEAs, DCISs and invasive carcinomas of the same patients were microdissected using PALM micro laser technology. DNA was isolated using the QIAamp DNA Micro Kit (QIAGEN). We have investigated a set of the polymorphic microsatellite markers D7S522, D8S522, NEFL, D10S541 (PTEN), D13S153 (RB1), D16S400, D16S402, D16S422 and D17S855 (BRCA1) using multiplex PCR for the detection of allelic imbalances. Most of the investigated FEAs showed a lower frequency of loss of heterozygosity than associated DCISs or invasive carcinomas. However, we were able to detect the same alterations in FEAs as in DCISs or invasive carcinomas in a number of cases. Notably, the microsatellite marker on 16q showed more prevalent allelic imbalances in FEAs than the other investigated markers. One of the hallmarks in the pathogenesis of a large subgroup of invasive breast carcinomas is the early loss of chromosome arm 16q. In this study, we were able to detect frequent genetic alterations on chromosome 16q in FEAs, associated DCISs and invasive carcinomas. This suggests that FEA is a precursor lesion in the low-grade pathway.