Current treatment for metastatic disease targets angiogenesis. With the increasing data demonstrating that cancer cells do not entirely rely on angiogenesis but hijack the existing vasculature through mechanisms such as co‐option of existing blood vessels, identification of targets has become of utmost importance. Our study looks at the vasculature of chemonaïve and treated colorectal carcinoma liver metastases (CRCLMs) to obtain a basic understanding of the microvessel density, type of vasculature (mature versus immature), and correlation with histopathological growth patterns that demonstrate unique patterns of angiogenesis. We performed immunohistochemistry on chemonaïve sections of desmoplastic histopathological growth pattern (DHGP) and replacement histopathological growth patterns (RHGP) lesions with CD31 [endothelial cell (EC) marker] and CD34/Ki67 double staining, which denotes proliferating ECs. The CD31 stains demonstrated a lower microvascular CD31 +ve capillary density in the DHGP versus RHGP lesions; and integrating both immunostains with CD34/Ki67 staining on serial sections revealed proliferating vessels in DHGP lesions and co‐option of mature existing blood vessels in RHGP lesions. Interestingly, upon treatment with chemotherapy and bevacizumab, the RHGP lesions showed no necrosis whereas the DHGP lesions had almost 100% necrosis of the cancer cells and in most cases there was a single layer of viable cancer cells, just under or within the desmoplastic ring. The survival of these cells may be directly related to spatial location and possibly a different microenvironment, which may involve adhesion to different extracellular matrix components and/or different oxygen/nutrient availability. This remains to be elucidated. We provide evidence that DHGP CRCLMs obtain their blood supply via sprouting angiogenesis whereas RHGP lesions obtain their blood supply via co‐option of existing vasculature. Furthermore current treatment regimens do not affect RHGP lesions and although they kill the majority of the cancer cells in DHGP lesions, there are cells surviving within or adjacent to the desmoplastic ring which could potentially give rise to a growing lesion.

Ochratoxin A (OTA) has been detected in high amounts in human blood samples collected in nephrology departments in Tunisia from nephropathy patients under dialysis, especially those categorised as having a chronic interstitial nephropathy of unknown aetiology. These represent 12-26.1% of all chronic renal failure patients. To clarify the situation, food and blood samples were collected from nephropathy patients and controls, (with no familial case of nephropathy). The OTA assay showed very different scales of OTA food and blood contamination from 0.1 to 16.6 micrograms/kg and 0.1-2.3 ng/ml, respectively, in controls and healthy individuals and 0.3-46 830 micrograms/kg for food and 0.7-1136 ng/ml for blood in nephropathy patients. The disease seems related to OTA blood levels and food contaminations, since the control group was significantly different from the nephropathy group (p < 0.005) for both food and blood ochratoxin A contamination. Combined with data published already, the results emphasize the likely endemic aspect of this OTA-related nephropathy occurring in Tunisia and possibly in other countries of northern Africa. This nephropathy is very similar to Balkan endemic nephropathy.

Ochratoxin A (OTA) is a nephrotoxic mycotoxin that is being increasingly considered as the main causal agent of Balkan endemic nephropathy (BEN), a fatal kidney disease associated with the end stage of urothelial tumours. However, despite the considerable amount of data, it is still controversial whether OTA plays a causative or only a subordinate role in the induction of this human nephropathy. Tunisia for years had to confront a very similar human nephropathy, which is tentatively called chronic interstitial nephropathy of unknown cause. This study tends firstly to consolidate the suspected link between this Tunisian chronic interstitial nephropathy (CIN) of unknown cause and the presence of OTA in the blood and food of such patients, and second to enlighten the endemic character of this particular nephropathy. Therefore, in four consecutive inquiries, performed within the period 1991-2000, blood and food OTA contaminations were assayed and compared for 954 nephropathy patients and 205 healthy subjects from the Tunisian general population. This survey was also designed to show that, although the whole population is likely to be exposed to OTA, specific people living in conditions showing similarities with the Balkans do have a kidney disease apparently linked to ochratoxin in food. The results showed that the highest incidences were found in patients with CIN of unknown cause. Indeed, the percentages of OTA-positive samples ranged from 93% to 100%, whereas it was only from 62% to 82% in healthy subjects. Mean OTA concentrations were also higher in patients with CIN of unknown cause than in controls (44.4±-19 mg/L to 55.6±-19 mg/L as opposed to 1.22±-1.2 mg/L to 3.35±-2.32 mg/L, respectively). This study emphasizes further the implication of OTA on this particular human nephropathy and underlines the probable causative role of OTA in the onset of this disease. It is important to note that the highest levels of food OTA contamination were found in the group presenting with CIN of unknown cause, indicating that, similar to the case in the Balkans, people are exposed to OTA essentially by their food.

The determination of ochratoxin A (OTA) in human blood in Tunisian populations is underway. The range of conta mination is between 0.7 to 7.8 ng ml-1 for the general popu lation and 12 to 55 ng ml-1 for people suffering from chron ic renal failure. It appears that 21 to 64% of people suffer ing from nephropathy are OTA positive with a detection limit of 1ng ml-1. This situation prompted us to search for possible association of OTA contamination and nephropa thy resembling Balkan endemic nephropathy. The classifi cation of the ill population into chronic interstitial nephropathy (CIN), chronic glomerular nephropathy (CGN), chronic vascular nephropathy (CVN) and others, indicated that the largest is the CIN group which is signifi cantly different from the other groups, and from the con trol (P < 0.005). Furthermore, it presented the highest OTA mean values (25 to 59 ng ml-1) compared with the control, CGN, CVN and other groups (6 to 18 ng ml-1) according to the designated region in Tunisia. The rural population seems to be more exposed to ochratoxins in Tunisia, as has been previously reported in the Balkans and Western Europe. Altogether, these results emphasise that in Tunisia an endemic ochratoxin-related nephropathy is probably occurring.

Claudin-2 promotes breast cancer liver metastasis by enabling seeding and early cancer cell survival. We now demonstrate that Claudin-2 is functionally required for colorectal cancer liver metastasis and that Claudin-2 expression in primary colorectal cancers is associated with poor overall and liver metastasis-free survival. We have examined the role of Claudin-2, and other claudin family members, as potential prognostic biomarkers of the desmoplastic and replacement histopathological growth pattern associated with colorectal cancer liver metastases. Immunohistochemical analysis revealed higher Claudin-2 levels in replacement type metastases when compared to those with desmoplastic features. In contrast, Claudin-8 was highly expressed in desmoplastic colorectal cancer liver metastases. Similar observations were made following immunohistochemical staining of patient-derived xenografts (PDXs) that we have established, which faithfully retain the histopathology of desmoplastic or replacement type colorectal cancer liver metastases. We provide evidence that Claudin-2 status in patient-derived extracellular vesicles may serve as a relevant prognostic biomarker to predict whether colorectal cancer patients have developed replacement type liver metastases. Such a biomarker will be a valuable tool in designing optimal treatment strategies to better manage patients with colorectal cancer liver metastases.