Value of Quantifying the Intratumoral Microvessel Density Based on Immunohistochemical Detection of PECAM-1 and vWF in Colorectal Carcinoma from Iraqi Patients

Abstract

Counting of newly formed microvessel may prove to be a useful tool in the early detection of metastatic potential and selection of patients for whom antiangiogenesis drugs might be beneficial.
Aim of the study: We designed this study to assess the significance of microvessel quantification in colorectal cancer with respect to different clinicopathological variables.
Subjects and Methods: forty archived paraffin embedded colorectal adenocarcinoma samples and their resection margins were enrolled in our study. Thin paraffin embedded sections (3-5μm thick) of both tumor and resection margins were prepared for each respective biopsy and were used to detect endothelial cell surface expression of PECAM-1 and vWF, by and immunohistochemistry technique.
Results: Based on the current outcome, there were significant differences in microvessel density based on PECAM-1 or vWF immunostaining when each tumor sample were compared to its respective resection margin (p<0.001and p<0.001, respectively). In addition, tumors ≥3mm3 in size demonstrated a significant increase in their microvessel density compared to their counterparts whether PECAM-1 or vWF immunostaining was applied (p<0.001 and p<0.001, respectively). Moreover, when tumor samples were analyzed based on their depth of invasion, for intratumoral microvessel count, exclusively, vWF immunostaining analysis demonstrated significant differences among the three groups SMP, SE, and OR since the latter came up with the highest microvessel count (p<0.05). When tumor lymph node metastases was questioned, exclusively, vWF immunostaining were significantly differentiated among N0, N1, and N2 groups (p<0.05). Concerning the possible correlations between the two investigated parameters in respect to various histopathological variables; both PECAM-1 and vWF immunostaining demonstrated significant positive correlations in tumor samples (r=0.37), whereas in resection margins, these correlations were absent. Although PECAM-1 and vWF immunostaining revealed significant and positive correlations within tumor differentiation (WD: r=0.56, MD: r=0.57, and PD: r=0.89) as well as with tumor stage (A-B: r=0.39 and C-D: r=0.31), still, they seem to correlate significantly and exclusively within SE group (r=0.74), tumors <3mm3 in size (r=0.66), N0 (r=0.36), and N1 (r=0.85) groups. However, PECAM-1 and vWF immunostaining revealed significant but negative correlation exclusively within N2 group (r= -0.38).
Conclusions: In conclusion, microvessel count could be useful as a predictor for tumor metastases in patients with colorectal adenocarcinoma. Possible interpretations of the current outcome are explained thoroughly in the text.