Significance of intratumoral microvessel density quantification based on immunohistochemical detection of PECAM-1 and vWF in colorectal carcinoma from Iraqi patients.
BACKGROUND
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.


OBJECTIVE
We designed this study to assess the significance of microvessel quantification in colorectal cancer with respect to different clinicopathological variables.


METHODS
Forty archived paraffin-embedded colorectal adenocarcinoma samples and their resection margins were enrolled in our study. Thin paraffin-embedded sections (3-5 m thick) of both tumor and resection margins were prepared for each respective biopsy and were used to detect endothelial cell (EC) surface expression of PECAM-1 and vWF by immunohistochemistry technique.


METHODS
For the comparison between tumor and resection margin regarding the investigated parameters, the t-test of significance was conducted. The association between surface expression of PECAM-1 and vWF along with tumor differentiation, depth of invasion and lymph node metastasis was performed by Chi-square (chi2 ) and ANOVA test as well as 95% confidence interval. On the other hand, the association between the investigated parameters and tumor stage as well as tumor size was performed by student t-test. The correlations between the two investigated parameters in respect to various clinicopathological parameters were calculated by correlation coefficient (r). Statistical significance was defined as P < 0.05. All statistical analyses were performed using SPSS statistical package for social and medical science version 15.0.


RESULTS
Based on the current outcome, there were significant differences in microvessel density based on PECAM-1 or vWF immunostaining when each tumor sample was compared to its respective resection margin (P < 0.001 and P < 0.001, respectively). In addition, tumors >or=3 mm 3 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: submucosa into muscularis propria (SMP), tumor reaches serosa (SE) and tumors invade other organs (OR), since the latter came up with the highest microvessel count (P < 0.05). When tumor lymph node metastases were 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 <3 mm 3 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.
Ahmed
Mohanad M
MM
Department of Microbiology, College of Medicine, Kerbala University, Kerbala, Iraq.
Mohammed
Suhad Hadi
SH
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001699:Biometry / Q000379:methods; D015179:Colorectal Neoplasms / Q000473:pathology*; D005260:Female; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods; D007493:Iraq; D008297:Male; D055806:Microvessels / Q000473:pathology*; D008875:Middle Aged; D009389:Neovascularization, Pathologic; D019408:Platelet Endothelial Cell Adhesion Molecule-1 / Q000032:analysis*; D014841:von Willebrand Factor / Q000032:analysis*
D019408:Platelet Endothelial Cell Adhesion Molecule-1; D014841:von Willebrand Factor