Critical evaluation of histochemical and immunochemical methods for the demonstration of vascular supply in rectal and oesophageal cancer

[Prognostic role of vascularisation and proliferation in rectal cancer with liver metastasis]

BACKGROUND

The present study was designed to provide an analysis of factors for angiogenesis and proliferation.

MATERIAL AND METHOD

We analyzed tumor tissues from 37 rectal cancer patients with concurrent or subsequent liver metastasis underwent preoperative radiotherapy, surgery and adjuvant chemotherapy. Immunohistochemistry was used for expression of proliferation (staining with anti-Ki67: MIB-1) and for detection of microvessel density (MVD, expressed by CD34). Clinicopathological findings were compared with outcome with emphasis to IHC.

RESULTS

A vascular enumeration and pN status and the time of presence of the metastases has shown prognostic role along with the factors above. Increased proliferative activity of the tumor as expressed by MIB-1 staining has no prognostic value, similarly to the localization of tumor, gender, age or grading.

SUMMARY

Different prognostic and predictive factors in colorectal cancer have been reported. Higher pN status and tumor vascularisation has been linked to poor prognosis in overall survival and tumor recurrence.

Distribution of newly formed vessels in human colorectal carcinomas with microangiography

OBJECTIVES

 Together, tumour cells and blood vessels compose a highly integrated ecosystem. This study was designed to investigate the distribution of newly formed vessels and the relationship of tissue structure to vascularity in human colorectal carcinomas.

SUBJECTS AND METHODS

 Microangiography, a silicone rubber compound injection method, was used successfully to study 18 resected colon cases. Vascular densities were evaluated by soft x-ray examination, and histological constitution was assessed by an ocular, square lattice, superimposing technique.

RESULTS

 On average, vascular density was 1.43 times greater (range 1.02-1.80) in tumour tissue than in normal mucosa. However, the vascular density in mucinous adenocarcinomas was significantly lower than that in well and moderately differentiated adenocarcinomas. When vascular densities were compared in an upper peripheral region (UR) and a lower central region (LR) (designated as upper and lower with reference to their position in relation to the submucosal vessels), the UR showed significantly higher vascular density than the LR. Histologically, the UR had a significantly higher density of carcinoma cells than the LR.

CONCLUSION

 These results suggest that the vascularity of colorectal carcinomas varies with respect to their topographical position and their histological subtypes.

Tumor invasion and angiogenesis in early esophageal squamous cell carcinoma

BACKGROUND AND OBJECTIVES

Although the relationship between angiogenesis and tumor proliferation or malignant potential has been previously demonstrated in several studies, early stage of cancer invasion and angiogenesis has seldom been investigated.

METHODS

From the esophageal specimens of eight recently resected cases with esophageal squamous cell carcinoma, 25 areas of carcinoma-in-situ or microinvasive carcinoma were selected, and then a serial histologic investigation and immunohistochemical staining for the detection of Factor VIII-related antigen to investigate microvessels in the lamina propria mucosae beneath the lesions as a measure of angiogeneses and staining for laminin to visualize basement membrane was performed. Lymphocyte infiltration below the lesions were also estimated. In view of early cancerous invasion, histologic patterns of the growth of the lesions were divided into "flat," "expansive," and "downgrowth" patterns.

RESULTS

Although downgrowth patterns are thought to be more invasive, relationships between the histologic patterns, and basement membrane staining patterns, and lymphocyte infiltration patterns were not demonstrated. However, the angiogenetic ratio (the number of vessels/cm under the lesions divided by that under normal epithelium) was observed to be significantly and closely related to tumor invasion patterns (P < 0.01), although it was not related to the destruction of the basement membrane or lymphocyte infiltration below the lesions.

CONCLUSIONS

The angiogenesis of esophageal squamous cell carcinoma is closely correlated to the tumor invasion patterns in early esophageal cancerous lesions.

Microvessel quantification and its possible relation with liver metastasis in colorectal cancer

BACKGROUND

Several studies have proven the usefulness of microvessel quantification as a prognostic factor for patients with various malignant tumors. The aim of this paper was to clarify the relationship between microvessel density (MVD) as a parameter of tumor angiogenesis and liver metastasis in colorectal cancer.

METHODS

A total of 175 patients with advanced colorectal cancer were evaluated (58 with concurrent liver metastases). Microvessel quantification was performed immunohistochemically, using monoclonal antibodies against endothelial protein Factor VIII-related antigen (F8RA) and against endothelial surface marker CD34. Finally, the relationship between MVD and liver metastasis was analyzed.

RESULTS

A significant correlation was observed between MVD for F8RA and MVD for CD34 (n = 175, r = 0.9560, P = 0.0001). MVD in the tumors stained for F8RA ranged from 15.2 to 78.6 microvessels per x 200 field (mean 32.8 +/- 11.7), while the tumors with liver metastatic disease compared with the tumors without liver metastasis (F8RA; mean 36.1 +/- 11.3 vs. 31.2 +/- 11.5, P = 0.0090; CD34; mean 64.4 +/- 20.4 vs. 52.0 +/- 19.4, P = 0.0010).

CONCLUSIONS

Microvessel quantification within a colorectal tumor using immunohistochemical staining methods has shown a significant correlation between MVD and liver metastasis. Tumors with a greater MVD may thus have a greater hematogenous metastatic propensity.

Microvessel quantification in primary colorectal carcinoma: an immunohistochemical study

The vascularisation of human primary colorectal carcinomas was studied immunohistochemically using the endothelial cell markers CD31 and factor VIII-related antigen. Tumour sections were systematically scanned at a magnification of x 100 to find areas of intense neovascularisation. Microvessel counts within these vascular 'hotspots' were performed at magnification x 250. Regions in which tumour cords were surrounded by a collagen IV-positive basement membrane were compared with those in which this was absent and with normal mucosa. CD31 appeared to be a more sensitive marker for endothelial cells than factor VIII-related antigen (mean 185 +/- 59 and 120 +/- 38 microvessels mm-2). Within individual tumour sections microvessel counts in vascular hotspots with highest vessel density correlated significantly with microvessel counts in vascular hotspots with second highest vessel density (P < 0.01). Microvessel counts in tumour areas where collagen IV-positive basement membrane were absent exceeded those in areas where it was present (factor of 1.7) and those in normal mucosa (factor of 1.6). The differences in vessel density between individual tumours and the low variability in vessel density within individual tumours using this quantification technique allow us to investigate the prognostic value of vessel density in areas of intense neovascularisation in human primary colorectal carcinomas.

Microvascular structure of benign and malignant tumors of the colon in humans

Studies of experimental tumors in rodents indicate that there are morphological abnormalities of the tumor microcirculation compared to normal tissues. The aim of this study was to examine the structure of the microvasculature in benign and malignant colonic tumors in humans using microvascular casting techniques. There were 15 adenocarcinomas, four benign sporadic adenomas, and three specimens from patients with familial adenomatous polyposis (FAP). A cast of the microvessels of these tumors was prepared by intraarterial administration of acrylic resin (Mercox) and the cast examined by scanning electron microscopy. Quantitative measures of the microvasculature were obtained from histological sections using stereological techniques in four carcinomas, two sporadic adenomas, and 12 adenomas from patients with FAP. Vascular casts of benign colonic adenomas showed that the microvasculature had a similar organization to normal colon. However, capillaries and venules were elongated and had increased diameters compared to normal. In adenomas greater than 3 mm in diameter, there was an increased density of microvessels in the spaces between tumor cells. Vascular casts of colonic carcinomas were characterized by a disorganized structure and increased density of microvessels. The organization of microvessels within carcinomas had a similar overall pattern to normal colon. However, the increased number and density of microvessels resulted in formation of nodular clusters of capillaries, formation of "sheets" of frequently anastomosing capillaries, or almost complete packing of the interstitial spaces of the tumor by capillaries in places. Most capillaries had a long and tortuous course and numerous capillary sprouts were identified. Tumor microvessels had greater mean diameters than normal. Extravasation of resin from microvessels in carcinomas was frequently seen. The vascular volume of carcinomas (23.1% +/- 12.2), sporadic adenomas (16.3% +/- 3.4), and adenomas > 3 mm diameter in patients with FAP (17.7% +/- 3.0) were significantly greater than in normal colon (11.0% +/- 4.2). This study indicates that there is an increased vascular density in benign and malignant tumors of the colon compared to normal colon. The presence of profusely anastomotic microvessels and frequent capillary sprouts is evidence of active neovascularization and suggests control of tumor growth could be achieved by modifiers of angiogenesis.

Cell kinetics evaluation of colorectal tumors after in vivo administration of bromodeoxyuridine

Although several biomarkers have been tested, Dukes' (or TNM) stage at diagnosis is still considered the only prognostic factor of clinical relevance in colorectal cancer. Among the various biomarkers, the fraction of cells engaged in DNA synthesis has been extensively investigated as an indicator of tumor aggressiveness. Bromodeoxyuridine (BUdR) is a non-radioactive thymidine analogue which is incorporated into DNA during the S-phase of cycling cells. In order to evaluate the relationships between cell kinetics and morphologic variables, 500 mg of BUdR were given i.v. to 46 patients with colorectal cancer prior to surgery. After operation, a large tumor sample was taken and processed for immunohistochemical detection of BUdR-labeled cells in various regions of the neoplasm and in normal colorectal mucosa. Smaller superficial tumor specimens were also incubated with 3H-thymidine (3H-TdR) for the autoradiographic identification of labeled cells. In the 43 evaluable tumors, the overall BUdR labeling index (BLI, percent of labeled cells) was significantly higher in carcinoma (20.30 +/- 0.86%, SEM) than in normal colonic mucosa (6.51 +/- 0.49%). BLIs in central and peripheral regions of carcinoma were closely correlated (r = 0.48, p = 0.003). In 21 neoplasms a high correlation between overall BUdR and 3H-TdR labeling index in the same tumor was observed (r = 0.57, p = 0.007). No evident association between overall BLI and clinical or morphologic parameters of the tumor was seen, including number of capillaries and ras-p21 protein expression. We conclude that BUdR immunostaining after in vivo administration of BUdR is a simple method for studying cell kinetics in various regions of colorectal cancer. BUdR labeling data are comparable to those obtained with in vitro incorporation of 3H-TdR.