Tumour basement membrane laminin in adenocarcinoma of rectum: an immunohistochemical study of biological and clinical significance

Well-defined basement membrane laminin was seen in 98/158 (62%) rectal adenocarcinomas stained by an immunoperoxidase method. Only 27 (28%) patients with laminin-positive tumours developed distant metastases, compared with 39 (65%) patients with laminin-negative carcinomas. The corrected 5-year survival rates for patients with laminin-positive and laminin-negative tumours were 65% and 23%, respectively. Twenty-five out of 30 (83%) well-differentiated adenocarcinomas and only 3/15 (17%) poorly differentiated tumours contained basement membrane laminin, with moderately differentiated carcinomas showing intermediate laminin status (70/110, 64%, laminin positive). Forty-three of 60 (72%) of laminin-negative tumours had metastasized to regional lymph nodes. These data suggest that laminin may be a marker for differentiation. However, laminin status yields information about tumour behaviour which is not confined to stage and grade, and multivariate analysis shows that it is a better indicator of prognosis than tumour grade as assessed by conventional histology. Although laminin status alone is a less useful predictor of prognosis than Dukes' stage, a patient with a laminin-positive adenocarcinoma of rectum is 2.7 times as likely to survive 5 years than a patient with a laminin-negative tumour. Assessment of laminin status, together with Dukes' stage is, therefore, commended as a more precise and objective indicator of prognosis than histological degree of differentiation in colorectal carcinoma.     

Immunohistochemical detection of cathepsin-d expression in prostate-cancer

Lysosomal proteases may be involved in facilitating cancer invasion and metastatic spread by degradation of basement membranes and intercellular matrix. Overexpression of cathepsin D, a lysosomal aspartyl protease, has been reported in different tumours and seems to constitute a prognostic factor for survival in patients with breast cancer. The current study investigates immunohistochemical staining using anti-cathepsin D monoclonal antobodies (M1G8) in prostate cancer specimens and tissue from patients with benign prostatic hyperplasia (BPH). Among 41 tumours expression of cathepsin D was observed in 14 of 26 (54%) low stage and grade tumours (T-1-2/G(1-2)) and in 12 of 15 (86%) high stage and grade tumours (T-3, G(3)). Cathepsin D positivity was found within the cytoplasm and at the surface of tumour cells localized in glandular structures and in single cells invading the prostatic stroma, while no staining was observed in normal prostatic tissue and in mesenchymal cells. Two of ten specimens from patients with benign prostatic hyperplasia showed a weakly positive staining reaction within glandular structures. The clinical course of localized prostate cancer appears to be highly variable and the different treatment strategies (radical prostatectomy, radiation therapy or surveillance) have come under debate. For the determination of the biological aggressiveness of prostate cancer in the individual patient easily available biological prognostic factors are needed. This report demonstrates overexpression of cathepsin D in prostate cancer specimens with increasing frequency in patients with tumours of high grade and stage. The usefulness of cathepsin D immunohistochemistry as a prognostic factor should be prospectively evaluated.     

Expression of fibronectin and laminin in the rat liver after partial hepatectomy, during carcinogenesis, and in transplantable hepatocellular carcinomas

The distribution in the F344 rat liver of two extracellular matrix and basement membrane components, fibronectin and laminin, was studied by immunofluorescence. Fibronectin was found diffusely in normal liver lining the sinusoids and in connective tissue surrounding blood vessels and bile ducts; laminin was present predominantly in the basement membranes of blood vessels and bile ducts and was only inconsistently seen lining the sinusoids. After partial hepatectomy (PH), there was a transient decrease of fibronectin in the central and midzone sinusoidal hepatic areas. This decrease was most marked on day 3 after the PH. Carcinogens caused marked changes in the distribution of fibronectin. Large extracellular deposits of fibronectin were seen in areas of oval cell proliferation in livers of rats treated with N-2-fluorenylacetamide (2-FAA) while being fed a choline-deficient diet. In contrast, the nodules that developed in these livers were almost completely devoid of fibronectin staining. Neoplastic nodules produced in rats by cyclic feedings of 2-FAA r by injections of diethylnitrosamine also contained little or no fibronectin. Laminin staining did not change markedly during these treatments, but increased staining was seen associated with the newly formed ductlike structures and oval cells in liver of rats treated with carcinogens. Transplantable hepatomas varied in their fibronectin staining from fibronectin-negative hepatomas to ones with fibronectin staining within or around every tumor cell. Laminin was only found around the vascular structures within the tumors. The presence or absence of fibronectin in hepatomas did not show an obvious correlation to growth rate or metastatic potential of the tumors studied.     

E-cadherin expression in bladder cancer using formalin-fixed,paraffin-embedded tissues: Correlation with histopathological grade,tumour stage and survival

To determine the potential prognostic value of epithelial cadherin (E-cadherin), a Ca²⁺-dependent cell-cell adhesion molecule, we have analysed its immunoreactivity and cellular localisation in 67 transitional cell carcinomas (TCC) using an avidin-biotin immunoperoxidase technique on formalin-fixed, paraffin-embedded tissues. These results were correlated with histopathological grade, tumour stage, presence of metastases and survival. In addition, 10 cystitis and 11 normal bladder biopsies were evaluated as controls. E-cadherin was expressed in a normal membranous pattern in all normal and 7 of 10 cystitis biopsies. Loss of normal surface E-cadherin was expression was found in 3 of 15 superficial tumours and in 48 of 52 invasive cancers. Abnormal immunoreactivity was strictly related to tumour differentiation and stage. Fifteen of 20 well-differentiated (grade 1) tumours showed preserved membranous E-cadherin immunoreactivity, while 46 of 47 moderate and poorly differentiated tumours (grades II and III) demonstrated abnormal staining patterns. Loss of membranous E-cadherin immuno-reactivity was also associated with advanced tumour stage. There was a significantly higher 5-year survival rate for patients with preserved membranous staining compared with patients with abnormal staining. © 1995 Wiley-Liss, Inc.     

The influence of local tissue environment on epithelial basement membrane continuity in colorectal carcinomas

For colorectal carcinomas, there is evidence that marked discontinuity of the epithelial basement membrane (EBM) is associated with higher malignant potential. Since the meta-static process appears to be selective, more discontinuous EBMs might be expected in secondary rather than in primary tumours. To test this prediction, we examined a series of 60 cases of colorectal carcinoma for which samples of lymph-node or liver metastases were available. Sections were immunocyto-chemically stained for laminin, and the continuity of tumour EBM was then assessed by observational rating as well as by detailed morphometric analysis for a sample of cases. Contrary to the above prediction, we find that EBMs tend to be more continuous in secondary tumours than in corresponding primary tumours. These results could be explained by the possibility that local tissue environmental factors have a major influence on EBM continuity. Supporting evidence comes from our previous observation that EBM is very discontinuous at the advancing edge of primary colorectal carcinomas, where the tumour is adjacent to collagen-I-deficient stroma. Further evidence from the present study is that the EBM is extremely discontinuous at the interface between metastases and specialised parenchymal tissue, but more continuous at the interface between metastases and stromal connective tissue. Since basement membranes affect the differentiation and behaviour of adjacent cells, these findings suggest that host tissues may influence invasive activity through their effects on EBM continuity.     

Immunohistochemical assessment of basement membrane components in colorectal cancer: prognostic implications

Loss of basement membrane integrity during neoplastic invasion may have some direct prognostic significance, which is worth investigating. We studied 151 cases of colorectal adenocarcinomas retrospectively. The aim of the study was to investigate the immunohistochemical expression as well as the distribution of laminin and collagen IV within the basement membranes of cancer cell formations. The results were related to histological grade of malignancy (I, II or III) and Dukes' staging of all tumours as well as to 3-year survival status in 52 patients. Using the immunostaining method of strept ABComplex/HRP and appropriate monoclonal or polyclonal antibodies, we assessed the continuity, the discontinuity of the distribution or the total loss of structural basement membrane components alongside the infiltrating borders of each tumour. The results were evaluated statistically. Either a considerable degree of discontinuity or a total loss of basement membrane components was more common in moderately and poorly differentiated adenocarcinomas (p = 0.002 and p = 0.005 for collagen IV and laminin, respectively) and they seemed to be adversely associated with survival status (p = 0.066 and p = 0.014 for collagen IV and laminin, respectively). Interestingly, no association with the stage of disease was noticed. The results of this study reinforce the value of laminin and collagen IV as possible prognostic factors independently to tumour stage. The total loss or considerable discontinuity of the basement membranes of cancerous cells can be considered as indicators of tumour aggressiveness.     

Immunohistochemical study of fibronectin and laminin on gastric cancer

Frozen samples of normal gastric tissue (n = 80), gastric adenocarcinoma (n = 80), lymphnode metastases (n = 17) and liver metastases (n = 2) were investigated immunohistochemically for determination of fibronectin (FN) and laminin (LM). On monoclonal antibody, FN was seen in the gland basement membrane, scattered tissue and the vessel basement membrane in normal gastric tissue. On polyclonal antibody, FN was seen in the gland surface cells, the stomach gland cells and some portions of muscle fiber cells in normal gastric tissue, too. On both monoclonal and polyclonal antibody, LM was seen in the gland basement membrane, the vessel basement membrane, the vessel endothelial cells, and the fibroblast in normal gastric tissue. But on polyclonal antibody, LM staining in gland basement membrane was thicker than monoclonal antibody. These demonstrated that the monoclonal antibody was superior to the polyclonal antibody in specificity. In gastric adenocarcinoma, FN was not seen in the carcinoma gland basement membrane but in the tissue around the carcinoma. These suggested that FN had a share in the malignant transformation and the fibrous tissue formation. LM was seen in the carcinoma gland basement membrane in eighteen of thirty-six well-differentiated adenocarcinomas and two of fourteen moderately-differentiated adenocarcinomas. Well-differentiated adenocarcinoma were divided into two groups; a LM-positive group, and LM-negative group. These two groups were then compared for vein eroding, and lymph-node metastases, and the differences between the two groups found to be slight and not significant.(ABSTRACT TRUNCATED AT 250 WORDS)     

Relationships between epithelial basement membrane staining patterns in primary colorectal carcinomas and the extent of tumour spread.

In colorectal cancer an association has been found between lack of epithelial basement membrane (EMB) immunostaining in the tumour centre and more extensive malignant spread. Interestingly, ultrastructural investigations suggest that EBM loss at the tumour periphery may be part of an invasive mechanism. To further assess the significance of EBM deficiencies in different tumour areas, we carried out a detailed study of the basement membrane laminin immunostaining patterns in 130 cases of colorectal carcinoma. We find that discontinuous EBM staining in the tumour centre is associated with poor tumour differentiation (p less than 0.005), presence of lymph-node metastases (p less than 0.02), and more advanced Dukes stage (p less than 0.02). The latter association is strengthened by excluding cases in which numerous polymorphonuclear leukocytes (PMNs) are present adjacent to EBM breaks, suggesting that these inflammatory cells are a confounding factor. Discontinuous EBM staining is more frequently observed in tumour deep to muscularis propria than in submucosal tumour (p less than 0.02), indicating intra-tumoral variation. At the tumour periphery, extensive EBM discontinuity shows no association with lymph-node involvement, but is linked with deeper local invasion (p less than 0.05). While EBM staining patterns around central and peripheral tumour glands are related (p less than 0.001), staining around peripheral glands is almost invariably more discontinuous. However, EBM lack at the tumour periphery is not as absolute as previously suggested, since in 18% of tumours fewer than 25% of peripheral tumour glands show EBM breaks. This appears consistent with the hypothesis that invasive changes at the tumour periphery are temporary and reversible.     

Altered expression of jack fruit lectin specific glycoconjugates in benign and malignant human colorectum

Lectins bind to terminal non reducing sugars of glycoconjugates in cell membranes and secretions. These glycoproteins can be very characteristic, both for the differentiation state of a tissue and for its grade of malignancy. The carbohydrate structures of cellular glycoconjugates in normal, adenoma, and carcinoma of human colorectum were analysed using HRP conjugated Jack Fruit Lectin (JFL). Fifty two rectal carcinomas, 18 adenomas and 25 normal rectal tissues were used for the study. Diaminobenzidine (DAB) was used as the visualant. Normal rectal tissues showed positive reaction with intense staining in more than 60% of the cells. Adenomas were seen to have moderate to intense staining with a range of 30 to 60% positive cells. The lowest levels of JFL staining were observed in invasive tumours. JFL binding was found to decrease with carcinomatous cells compared to adenomas and normal cells. A significant negative association was found between JFL binding and histologic abnormality (r = -0.85, P <0.0000). These results suggest that there are alterations in the carbohydrate structures of cellular glycoconjugates, which can be related to goblet cell differentiation, in normal, benign and malignant human colorectal tissue.     

纤维连接蛋白及层黏连蛋白在食管癌表达的研究

目的研究纤维连接蛋白、层黏连蛋白在食管癌中的表达及意义。方法采用免疫组化法分别检测60例食管癌患者纤维连接蛋白、层黏连蛋白的表达,正常食管组织标本、不典型增生食管组织标本各15例作为对照。结果在正常食管组织向恶性转化过程中,连续线状表达减少,碎片状表达增加;纤维连接蛋白(FN)、层黏连蛋白(LN)表达与食管癌病理分级、淋巴结转移有关;FN、LN在癌细胞胞质中阳性表达与食管癌病理分级、有无淋巴结转移无关;癌细胞胞质中FN与LN表达之间有明显的正相关性。结论基底膜FN、LN表达可作为临床判断食管癌分化程度及有无转移的有用指标;癌细胞胞质中FN与LN表达之间的正相关性提示在食管癌发展中两者有内在关联性;FN、LN表达异常对食管癌预后评估有一定意义。     

Laminin immunodetection in tumorous and nontumorous disorders of human thyroid

Laminin distribution in tissues from surgically removed thyroids consisting in normal gland (5), Basedow's disease (5), thyroiditis (5), follicular adenomas (8), papillary carcinomas (8), follicular carcinomas (6) was studied using rabbit laminin antibody raised against murine laminin. Immunoperoxidase technique (Avidin-Biotin-Peroxidase Complex) was performed on (1) paraffin sections of fixed tissue (2) frozen sections for light microscopy examination. Vibratome thick sections (100 micron) and pre-embedding technique were used for electron microscopy study. Positive staining, was obtained only on frozen and vibratome sections and was found within basement membranes but never in epithelial cell cytoplasm. Laminin had a similar distribution in follicular adenomas, Basedow's disease and normal tissue. Nests of damaged cells in Hashimoto's thyroiditis lacked positive laminin immunostaining. In papillary carcinomas positive staining was found beneath the epithelial cells along the cores. In well differentiated follicular carcinomas the perifollicular laminin staining was preserved, whereas in poorly differentiated follicular carcinomas laminin staining was barely visible or absent.     

Distribution of fibronectin and laminin in early and advanced signet-ring-cell carcinomas of the stomach

An immunoperoxidase method was used to compare the distribution of fibronectin and laminin between superficially spreading and deeply infiltrating parts of signet-ring-cell carcinoma of the stomach. In both parts, laminin-containing basement membranes were generally scarce, but they were observed on some of the cancer cells which had differentiated to glandular cells. Intramucosal invasion fronts of superficially spreading cancers often showed a layered structure, consisting of a middle zone of small cancer cells together with a superficial and a deep zone of signet-ring cells. In this structure, linear fibronectin and laminin deposits were common on the cancer cells in the deep zone, but rare in the superficial zone. However, fibrillar fibronectin deposits in the stroma were not considerably larger in either zone. At extramucosal invasion fronts of deeply infiltrating (advanced) cancers, a stromal remodelling with an increased amount of fibrillar fibronectin deposits was often observed around the cancer cells, whose cell surface fibronectin was largely lost even from some basement membranes. These findings suggest that invasive activity of signet-ring-cell carcinoma may not be related to the mere presence or absence of cell-surface fibronectin and laminin but to the amount of stromal fibronectin, which could reflect a cell-stroma interaction. Signet-ring-cell carcinomas have a stage of intramucosal growth in which cancer cells may live in dependence upon the pre-existing stroma and form the layered structure, while in advanced stages cancer cells seemed to have acquired an ability to elicit their own “tumor stroma”.     

The prognostic value of the monoclonal antibodies HMFG1 and HMFG2 in breast cancer

The monoclonal antibodies HMFG1 and HMFG2 identify antigens of the milk fat globule membrane which are also found on breast epithelial cells. Immunohistochemical staining was performed using both antibodies on formalin fixed, paraffin embedded sections of 93 breast carcinoma, 36 histologically benign lesions and 29 histologically normal breast tissue blocks. In both normal and benign breast disease the staining was largely extracellular whilst in malignant tissue the staining was variable and often intracellular. Nine carcinomas did not stain with either antibody. The staining patterns of malignant tissues were graded and no correlation was found between the grades and survival or indices of prognosis, (the oestrogen receptor status, Bloom's grade and the presence or absence of metastases to the axillary nodes.) This study indicates that with the present methods available for grading staining patterns, although of diagnostic value, these monoclonal antibodies are unlikely to assist in determining either the degree of tumour differentiation or prognosis in breast carcinoma.     

Lack of correlation between metastasis of human rectal carcinoma and the absence of stromal fibronectin.

In a retrospective study we have used an immunoperoxidase procedure to localize the glycoprotein fibronectin in human rectal carcinomas, concentrating on tumour invading thick-walled extramural veins. Fibronectin was present in 29 out of 38 cases, in connective tissue stroma, and was not in direct association with the tumour cells, except in areas of necrosis. We found no correlation between the presence or absence of stromal fibronectin and (1) the degree of cellular differentiation within the tumour, (2) tumour progression (Dukes'' classification) (3) the subsequent development of metastases and (4) patient longevity. OUr results do not support the conclusions from in vitro studies (Smith et al., 1979) that the metastatic potential of carcinomas may be partly determined by the ability of tumour cells to synthesize pericellular fibronectin.     

Thymidine phosphorylase and dihydropyrimidine dehydrogenase protein expression in colorectal cancer.

It is essential for actively proliferating cells to increase their rate of DNA synthesis to progress through the cell cycle. This is reflected in the increased uracil usage that is a common feature in solid tumours. Thymidine phosphorylase (TP) anabolises formation of pyrimidine nucleosides available for DNA synthesis, whereas dihydropyrimidine dehydrogenase (DPD) catabolises the degradation of pyrimidine bases, thereby reducing levels of uracil and thymine available for DNA synthesis. In addition, tissue levels of TP or DPD have been associated with the clinical efficacy of pyrimidine anti-metabolites commonly used in the treatment of colorectal cancer. There is little information, however, on the relative expression or degree of co-ordinated regulation of either protein in primary or metastatic colorectal cancer. DPD and TP protein levels were measured in 15 primary colorectal carcinomas, 10 colorectal liver metastases and 25 adjacent uninvolved tissues. DPD was reduced in 67% (10/15) of colorectal tumours (mean tumour/normal = 0.52) and in all liver metastases (mean tumour/normal = 0.41) compared with the corresponding normal tissue. In contrast, TP was increased in 80% (12/15) of colorectal tumours (mean tumour/normal = 18.91) and in all metastases (mean tumour/normal = 3.70). TP and DPD protein expression were highly variable in uninvolved and tumour tissues. The ratio of TP:DPD was higher in 87% of colorectal tumours and in all liver metastases compared with the adjacent uninvolved tissues. This suggests the presence of co-ordinated regulation of these pyrimidine metabolic enzymes and offers a strategy for optimising the use of pyrimidine-based chemotherapy.     

Distribution of laminin and fibronectin isoforms in oral mucosa and oral squamous cell carcinoma

The expression of laminin and fibronectin isoforms varies with cellular maturation and differentiation and these differences may well influence cellular processes such as adhesion and motility. The basement membrane (BM) of fetal oral squamous epithelium contains the laminin chains, alpha2, alpha3, alpha5, beta1, beta2, beta3, gamma1 and gamma2. The BM of adult normal oral squamous epithelium comprises the laminin chains, alpha3, alpha5, beta1, beta3, gamma1 and gamma2. A re-expression of the laminin alpha2 and beta2 chains could be shown in adult hyperproliferative, dysplastic and carcinomatous lesions. In dysplasia and oral squamous cell carcinoma (OSCC), multifocal breaks of the BM are present as indicated by laminin chain antibodies. These breaks correlate to malignancy grade in their extent. Moreover, in the invasion front the alpha3 and gamma2 chain of laminin-5 can immunohistochemically be found outside the BM within the cytoplasm of budding carcinoma cells and in the adjacent stroma. The correlation between the morphological pattern of invasive tumour clusters and a laminin-5 immunostaining in the adjacent stroma may suggest, first, that a laminin-5 deposition outside the BM is an immunohistochemical marker for invasion and second, that OSCC invasion is guided by the laminin-5 matrix. Expression of oncofetal fibronectins (IIICS de novo glycosylated fibronectin and ED-B fibronectin) could be demonstrated throughout the stromal compartment. However, the ED-B fibronectin synthesizing cells (RNA/RNA in situ hybridization) are confined to small stroma areas and to single stroma and inflammatory cells in the invasion front. A correlation of the number of ED-B fibronectin synthesizing cells to malignancy grade could not be seen. ED-B fibronectin mRNA-positive cells seem to be concentrated in areas of fibrous stroma recruitment with a linear alignment of stromal fibro-/myofibroblasts (desmoplasia). Double staining experiments (ED-B fibronectin in situ hybridization and alpha-smooth muscle actin immunohistochemistry) indicated that the stroma myofibroblasts are a preferential source of ED-B fibronectin. In conclusion, in OSCC, a fetal extracellular matrix conversion is demonstrable. Tumour cells (laminin alpha2 and beta2 chain) and recruited stromal myofibroblasts (oncofetal ED-B fibronectin) contribute to the fetal extracellular matrix milieu.     

Carbonyl reductase and NADPH cytochrome P450 reductase activities in human tumoral versus normal tissues

The use of bioreductive agents in enzyme-directed bioreductive therapy has been proposed to take advantage not only of hypoxia in tumours, but also of the presence of reductases that metabolise such compounds. In this study, we studied the activities of NADPH cytochrome P450 reductase (P450R) and carbonyl reductase (CR) in 17 human lung tumours and 18 human breast tumours, together with the corresponding normal tissues. For lung cancer but not for breast cancer there was a significant difference in the CR activity between normal and tumour tissue. CR activity was increased with respect to the normal tissue between 2-fold and 40-fold indicating heterogeneity in tumour samples. No relationship was found between CR activity and the histological type, tumoral grade or TNM stage of the tumours. Although some variation in P450R activity in tumoral versus normal tissues was found in the majority of the samples studied, no significant differences could be demonstrated.     

Expression of tissue inhibitor of metalloproteinases TIMP-2 in human colorectal cancer--a predictor of tumour stage.

The aim of this study was to investigate whether immunohistochemical staining patterns of tissue inhibitor of metalloproteinases TIMP-2 and matrix metalloproteinases MMP-2 and MMP-9 can be predictors of tumour stage and survival time in colorectal cancer. Frozen tumour sections from 212 patients operated on between January 1987 and November 1990 were investigated. Three mouse monoclonal antibodies--T2-101 against TIMP-2, CA-4001 against MMP-2 and GE-213 against MMP-9--were used. Positive expression of TIMP-2 (a) in basement membranes and (b) diffusely in stroma with (c) subglandular enhancement was found significantly (P < 0.01, P < 0.05, P < 0.05) more often in localized tumours than in tumours with regional or distant metastases. Neither pattern correlated with tumour differentiation. Patterns (a) and (c) correlated with longer survival time (P < 0.05); (b) reached near significance (P < 0.07). When the survival analyses were restricted to potentially cured patients, neither pattern could foretell death from cancer. Positive expression of MMP-2 in tumour epithelium and of MMP-9 in tumour-infiltrating macrophages were both independent of tumour stage and were without correlation with survival time. A large number of MMP-9-positive macrophages correlated (P < 0.05) with poor tumour differentiation, whereas weak or absent epithelial MMP-2 staining reached near significance (P < 0.08). Exploration of TIMP-2 expression is valuable for the discrimination between macroscopically localized and metastatic colorectal cancer, but it cannot predict which of the potentially cured patients are likely to have micrometastases. MMP-2 and MMP-9 stainings are of minor value in staging and prognostic prediction.     

p53 immunohistochemistry in transitional cell carcinoma and dysplasia of the urinary bladder correlates with disease progression.

Immunohistochemically detectable p53 protein using a polyclonal antibody (CM-1) was studied in 42 carcinomas of which 11 were grade I, 22 grade II and nine grade III carcinomas. Additionally 14 urothelial dysplasias were studied. In 11 of these a diagnosis of transitional cell carcinoma was established before and in one after the dysplasia diagnosis. Twenty-one out of 42 (50%) cases of transitional cell carcinoma were positive for the p53 protein. Eleven out of 14 (78%) dysplasias and 10/12 (83%) related carcinomas were p53 positive. One out of 11 grade I (9%), 12/22 grade II (55%) and 8/9 grade III (89%) tumours showed positivity for p53. There were significantly more p53 positive cases in grade II-III tumours than in grade I tumours (P = 0.004). There were significantly more p53 positive cases in stage T2-T4 tumours than in stage T1 tumours (P = 0.035). In only one case among the 11 dysplastic lesions following the treatment of a carcinoma the dysplastic lesion was p53 negative while the preceding carcinoma was p53 positive. All dysplasias and 28 carcinomas were also immunostained for laminin and type IV collagen to evaluate the continuity of basement membranes (BMs). Clearly disrupted BMs were observed only in grade III carcinomas. These cases showed the most p53 immunopositivity. The results show a strong association of p53 staining between dysplasias and transitional cell carcinomas of the urinary bladder indicating that these lesions might share similar p53 changes. The correlation to grade, clinical stage and to disrupted BM suggests that p53 mutations may be associated with the evolution of aggressive growth characteristics in transitional cell carcinomas or, alternatively, that p53 positive tumours of a more aggressive type from the start. Whether p53 staining can be used as an adjunct in the assessment and follow-up of epithelial changes of patients treated for a p53 positive bladder carcinoma deserves to be studied.     

Extracellular matrix proteins and chemoradiotherapy: alpha5beta1 integrin as a predictive marker in rectal cancer.

AIMS: To investigate the effects of extracellular matrix (ECM) protein expression on the rates of apoptosis and proliferation in rectal cancers and subsequent response to chemoradiotherapy (CRT). METHODS: The expression of fibronectin, collagen IV, laminin and the fibronectin receptor (FnR, alpha5beta1 integrin) were analysed in 32 pre-treatment rectal cancer biopsies by immunohistochemistry. ECM expression was correlated with tumour mitotic index (MI), apoptotic index (AI) and histopathological response to CRT. RESULTS: 18/32 cancers showed a poor response and 14/32 a good response (5/14 with complete pathological response) to CRT. Moderate to strong staining was seen in 22/32 cancers for fibronectin, 5/32 for collagen IV and 18/32 for laminin. Tumour FnR was related to stromal fibronectin content, and was significantly associated with CRT response; good responders having higher FnR expression compared to poor responders. No association was found between FnR expression and either MI or AI in pre-treatment biopsies, nor between MI or AI and CRT response. CONCLUSIONS: Tumour FnR expression is independent of MI and AI, and may serve as a useful marker for CRT response in rectal cancer.