Biomedical subjects

Charlotte F J M Peeters

Publications and source records attributed to Charlotte F J M Peeters.

4 recordsLinked to original sources

PubMed2006

Outgrowth of human liver metastases after resection of the primary colorectal tumor: a shift in the balance between apoptosis and proliferation.

Rapid outgrowth of metastases after removal of the primary tumor has been described in several mouse models. Loss of primary tumor-induced inhibition of angiogenesis in the metastases has been suggested as the underlying cause. Accordingly, we recently demonstrated that vascular density in human colorectal liver metastases increases after primary tumor resection. Here, we investigate whether this increase in vascular density has, in its turn, effects on the tumor growth of the liver metastases. We analyzed tumor growth in synchronous liver metastases from patients with the primary tumor in place, in synchronous metastases from patients with the primary tumor resected and in metachronous metastases. Tumor growth was studied by assessing the percentage of cells undergoing apoptosis by activated caspase-3 staining, and the percentage of proliferating cells by Ki-67 staining. While the percentage of proliferating cells within the metastases showed a modest increase after primary tumor resection, a significant decrease in the percentage of apoptotic cells was observed. Taken together, an increased net tumor growth of the metastases occurred after primary tumor resection. This acceleration of tumor growth could be confirmed by studying biopsies taken from the same patient before and after tumor resection. Our data show that in human cancer patients, a primary tumor may inhibit the growth of its liver metastases.

Adult↗

PubMed2005

Decrease in circulating anti-angiogenic factors (angiostatin and endostatin) after surgical removal of primary colorectal carcinoma coincides with increased metabolic activity of liver metastases.

Removal of a primary colorectal tumor resulted in an increase in metabolic activity in its liver metastasis. Concomitantly, levels of angiostatin and endostatin in urine and plasma, respectively, dropped. This finding indicates that the primary tumor suppressed angiogenesis in its distant metastasis, and that removal of the primary lesion caused a flare-up in vessel neoformation and, thus, enhanced metabolic activity in its liver metastasis.

Aged↗

PubMed2005

Progressive loss of endothelial P-selectin expression with increasing malignancy in colorectal cancer.

Adhesion of inflammatory cells to vascular endothelium is mediated by specific cell adhesion receptors on both leukocytes and endothelial cells. One of the adhesion molecules on the endothelium is P-selectin. Decreased vascular P-selectin expression has been associated with tumor progression in melanoma patients. We now report on the expression of endothelial P-selectin in colorectal cancer (CRC). We studied a colorectal tissue specimen series ranging from normal colorectal tissue via unmetastasized primary tumors to tumors with the same depth of invasion at the primary site but with liver metastases. Moreover, P-selectin expression levels in liver metastases were determined. The number of P-selectin positive vessels as a fraction of the total number of vessels, both intra- and peritumorally, was determined by staining for CD62P and CD34, respectively. Furthermore, by immunostaining for leukocytes (CD45) and macrophages (CD68), it was evaluated whether levels of P-selectin expression influenced infiltrate density and composition. The results showed that levels of peritumoral P-selectin expression were reciprocal to the degree of progression in CRC. This relation was even more pronounced intratumorally: in metastasized primary tumors and in the metastatic lesions, P-selectin expression was virtually absent. This distribution pattern was reflected in the numbers of leukocytes that accumulated in the various tissues, since in the primary tumors with metastases, and in the metastatic lesions, hardly any infiltrating cells were observed. In these lesions, leukocytes were present in the peritumoral zone, but seemed unable to enter the tumor tissue. In primary tumors without metastasis, the intratumoral leukocyte infiltration density was significantly higher. Recruitment levels of macrophages remained constant throughout the different tissues. We suggest that downregulation of endothelial P-selectin expression is a mechanism by which CRC lesions evade inflammatory regression and, thereby, progress to a more advanced stage of malignancy.

Aged↗

PubMed2004

Vascular density in colorectal liver metastases increases after removal of the primary tumor in human cancer patients.

In animal models, explosive growth of metastases after removal of the primary tumor has been attributed to abolishment of angiogenesis inhibition. We investigated the influence of (removal of) the primary tumor on vascularization of liver metastases in human colorectal cancer patients. We analyzed vascular density in synchronous liver metastases from patients with the primary tumor in situ, in synchronous metastases from patients with the primary tumor resected and in metachronous metastases. In a limited number of cases, biopsies from metastases from the same patient before and within 3 months after resection were analyzed. In addition, vascular density in metastases was compared to the vascular density in the corresponding primary tumor. Peritumoral and intratumoral vascular density were determined by staining for endothelial antigens CD31 and CD34, respectively. Both peritumoral and intratumoral vascular density were elevated in synchronous metastases from patients with the primary tumor removed compared to synchronous metastases from patients with the primary tumor in situ. Comparable results were observed in patients with metachronous metastases. An increase in vascular density after resection of the colorectal malignancy was also observed in biopsies taken from the same patient before and after tumor resection. Remarkably, vascular density in the liver metastases was always lower than that in the corresponding primary tumor. Our data show for the first time in humans that the presence of a primary tumor is correlated with decreased vascularization of its distant metastases. Resection of the primary tumor results in an increased vascularization of metastatic lesions.

Adult↗