Blood group-related antigens in human urothelium: enhanced expression of precursor, LeX, and LeY determinants in urothelial carcinoma

Seven mouse monoclonal antibodies and the lectin from Ulex europaeus, detecting blood group specificities of the ABH and Lewis systems, have been used to define the expression and/or modulation of these antigenic structures in human normal urothelium and tumors of the urinary bladder. The reagents employed recognize the following blood group related antigens: A, B, H, Lewisa (Lea), Lewisb (Leb), Lewisx (Lex), Lewisy (Ley), and type 1 precursor chain. Immunohistochemical studies have demonstrated that these antigenic systems are differentially expressed in the urothelium of secretor and nonsecretor individuals. The normal urothelium of secretors is particularly rich in ABH blood group antigens as well as Leb and Ley specificities. Nonsecretors, however, either lack or show decreased and patchy expression of H, Leb, and Ley antigens. In general, areas affected by carcinoma in situ showed deletion of ABH, as did invasive carcinomas, as demonstrated by other investigators. This was not a universal observation, however, as variable expression of ABH antigens occurred in a few invasive tumors. Lex antigen was not expressed in normal urothelium except for occasional umbrella cells, but was demonstrated in the majority of invasive tumors, regardless of blood type and secretor status of the individuals studied. Ley determinant, which was poorly expressed in the normal urothelium of nonsecretor individuals, was found in all tumors analyzed. An accumulation of non-fucosylated precursor structure was also a feature of invasive carcinoma, particularly in secretor individuals. A panel of anti-blood group antibodies, encompassing A, B, Lex, Ley and type 1 precursor chain specificities for use in patients of known secretor status, may provide useful early markers of malignant change in the urothelium.     

ABH and Lewis blood group expression in colorectal carcinoma

The expression of ABO(H) and Lewis blood group antigens on 68 colorectal carcinomas from 63 patients was studied by immunohistochemical staining of tissue specimens. The pattern of antigen expression was as follows: ABH was expressed in normal tissue only in secretors and was expressed in the proximal but not distal colon. In tumors, there was net loss of ABH expression in the proximal and net gain in the distal colon. Some nonsecretor tumor tissue expressed ABH. Lewis expression was similar to but less strong than ABH. Its expression occurred only in secretors and in normal epithelium only in the proximal colon. In tumors there was net loss of antigen expression proximally and net gain in the distal colon. There was no expression of Lewisb in tumors of nonsecretors. Lewisa antigen was expressed throughout the normal colon in secretors and nonsecretors with no discernible difference between proximal and distal colon. In tumors, net loss of expression of Lewisa occurred throughout the colon. No inappropriate blood group expression was observed in this study. With few exceptions, H expression paralleled expression of A and B in non-0 patients. Metastatic tumor antigen expression was similar to that of the primary in most cases. Alterations in antigen expression were not clinically or histologically distinctive.     

Activity of the human blood group ABO, Se, H, Le, and X gene-encoded glycosyltransferases in normal and malignant bladder urothelium

Immunohistochemistry has led to the finding of an expression of ABO-related blood group antigens in normal and malignant bladder urothelium which is different from that found on erythrocytes from the same individual. This includes a loss of blood group ABO expression in malignant urothelium, and the expression of Leb antigens in normal and malignant cells from individuals with Le(a+b-) and Le(a-b-) erythrocytes. To elucidate the mechanism of this blood group antigen expression in urothelium we have analyzed the activity of the specific glycosyltransferases encoded by the ABO, Se, H, Le, and X blood group genes in normal and malignant urothelium. Biopsies of normal urothelium were obtained from 22 individuals and biopsies of urothelial tumors from 20 individuals. The tissue donors were typed for ABO, Lewis, and secretor status on erythrocytes and saliva. The biopsies were disaggregated to single cell suspensions, and the activity of the individual glycosyltransferases was determined as pmol of labeled sugar incorporated by oligosaccharide acceptors per 100,000 cells. The A (alpha-3-N-acetyl-D-galactosaminyl) and B (alpha-3-D-galactosyl) gene-specified transferases showed no activity in malignant cells, whereas all other enzymes examined were expressed in both normal and malignant cells. Secretors and nonsecretors showed the same alpha-2-L-fucosyltransferase activity in both normal and malignant cells, whereas the alpha-3-L-fucosyltransferase was reduced (P less than 0.02) in malignant cells from Lewis positive individuals. The Lewis gene-encoded alpha-4-L-fucosyltransferase showed a similar activity in Lewis positive and negative individuals. These results indicate that the disappearance of A and B blood group antigens in bladder tumors and the expression of Leb antigens in normal and malignant cells from individuals with Le(a+b-) and Le(a-b-) erythrocytes are due to corresponding differences in glycosyltransferases. The results indicate that the ABO, H, Se, and Le genes are subjected to a tissue-dependent differential expression.     

Blood group ABO and Lewis antigen expression during neoplastic progression of human urothelium. Immunohistochemical study of type 1 chain structures

The deletion of blood group ABO antigen expression in bladder carcinoma has attracted attention because of its potential as a prognostic parameter. Based on recently produced monoclonal antibodies against blood group antigens, it has become possible to elucidate the carcinoma-associated modulation of these antigens at a molecular level. In this study we have used a panel of monoclonal antibodies (H, Lea, Leb, A, ALeb) that are specific to type 1 chain structures. By the use of an immunohistochemical method, the histologic and cytologic location of these antigens in the urothelium was studied in 25 biopsies from transitional cell carcinomas and compared to 21 previously examined normal biopsies. Urothelial blood group reactivity was compared to Lewis and secretor status. The authors found a series of events associated with neoplastic progression of noninvasive urothelium: a disruption of the orderly stratification of blood group antigens in different cell layers; cytostructural relocation of cytoplasmic antigens to the cell surface; loss of correlation between urothelial blood group antigens and secretor status; and gradual deletion of antigens. In the invasive tissue these events were followed by a total deletion of A and H isoantigens and uniform expression of Lewis b and sialyted Lewis a antigen. These findings indicate that there is a complex modulation of blood group antigen biosynthesis associated with the neoplastic progression of the human urothelium.     

A, B, H antigen expression in transitional cell carcinomas of the urinary bladder

The prognostic value of A, B, H blood group antigen determination in superficial bladder cancer is unclear. Recent immunohistochemical studies employing monoclonal antibodies and Ulex Europaeus Agglutinin I (UEA-I) (Vector) have shown that A, B, H detectability and distribution in non-neoplastic urothelium are influenced by methodologic factors and, most importantly, by the secretor status. The authors investigated the A, B, H antigen in 93 tumors of the urinary bladder (78 secretors, 15 nonsecretors) and semiquantified the alterations from the expected normal expression on a scale from 0 to 3. Four O saliva nonsecretors as expected showed no staining and were excluded. Eighty tumors showed abnormal A, B, H expression and in 37 of these, A, B, H antigens were not detected. Tumors of A and O individuals showed statistically different reactivities, probably related to differences in the specificity of the employed A- and H-reagents. A, B, H expression was influenced by stage and grade (P less than 0.05, P less than 0.10) and was correlated to the clinical course of A but not O patients. These results, suggesting that alterations in the A, B, H expression occur early in the neoplastic development and follow the synthetic pathways in an opposite direction, emphasize that reagents recognizing blood group precursor substances, common to all individuals irrespective of the ABO and saliva secretor types, may increase the prognostic accuracy of blood group antigen determination in bladder cancer.     

Immunohistologic expression of blood-group antigens in normal human gastrointestinal tract and colonic carcinoma

A panel of 7 mouse monoclonal antibodies and the lectin from Ulex europeus, detecting blood-group-related antigens of the ABH and Lewis systems, have been used to define the distribution of these antigenic structures within the human gastrointestinal tract, and to characterize their expression and modulation in colorectal carcinomas. The reagents employed detect the following blood-group specificities: A (all variants), B, H (type 2), Lewisa, Lewisb, X (Lewisx), Y (Lewisy) and type 1 precursor chain. Immunohistochemical studies demonstrate that these antigens are differentially expressed in various cell types and developmental stages of the human gastrointestinal tract. ABH expression undergoes developmental modulation in the human colorectal tract from positive to negative during embryogenesis, and is lost in adult cells. Colorectal tumors exhibit neosynthesis of ABH specificities that appear in tumor cells, and accumulation of the precursor antigens. They also show increased expression of Lewis antigens, especially Y determinant, which has a restricted pattern of distribution in normal tissues and is not found in normal colonic mucosa. Enhancement of the Lewis antigens is observed in all colorectal tumors analyzed, regardless of blood-group type and secretory status of the individuals studied. Tumor modulation of these antigens may be related to activation of suppressed genes and enhancement of fucosyltransferases.     

Clinical implications of the expression of epidermal growth factor receptors in human transitional cell carcinoma.

To evaluate the distribution and density of epidermal growth factor (EGF) receptors (EGF-Rs) on urothelium, immunohistological studies using a monoclonal antibody to the binding portion of the human EGF-R were performed on frozen specimens of normal urothelium (N = 20), urothelium from patients with nonurothelial urological malignancies (N = 15) and inflammatory diseases (N = 8), low grade superficial transitional cell carcinomas (TCC) (N = 13), high grade superficial or invasive TCC (N = 28), and endoscopically normal appearing urothelium from patients with low grade superficial (N = 5) or high grade (N = 21) TCC elsewhere in the bladder (or ipsilateral renal pelvis/ureter). EGF-Rs are found only on the basal layer of epithelial cells (with scattered representation on intermediate cells) in 95% of normal urothelial specimens and 100% of pathological specimens without urothelial malignancy. Alternatively, 92.3% of specimens of low grade superficial TCC and 100% of high grade TCCs had EGF-Rs richly expressed on the superficial as well as the deeper layers of urothelium. This "malignant" distribution of EGF-Rs was also found on all specimens of endoscopically normal appearing urothelium in patients with TCC elsewhere. The density of EGF-Rs correlated closely with tumor grade on both "premalignant" and frankly neoplastic urothelium. We conclude that the expression of EGF-Rs on urothelium favors the interaction of premalignant and malignant tissue with urinary EGF. To determine if altering the physiochemical environment of urine could interfere with this interaction, the effects of pH on the binding of and growth responses to EGF were assessed on four human TCC cell lines. Scatchard plots demonstrated that varying pH from 5.0 to 7.5 did not significantly change the total number of receptors, but EGF-R affinity was reduced approximately 20-fold as pH decreased from 7.5 to 5 in each TCC target. Similarly, significant growth stimulation by EGF at pH 7.5 was abrogated at pH less than or equal to 7.0 while growth rates in the absence of EGF remained unchanged at lower pHs. It thus appears that urinary acidification may hold promise in the management and prevention of recurrent bladder cancer.     

Lewis a antigen in transitional cell tumors of the urinary bladder

The failure of A,B,H antigens as prognostic parameters in noninvasive bladder cancer of blood group O individuals, who constitute 44% of the population, encouraged the evaluation of the closely related Lewis a antigen. Ninety-three tumors of the urinary bladder were stained employing the Tween 20 (Merck)-modified immunoperoxidase staining technique and serial dilution of monoclonal anti-Lewis a antibodies. On the basis of recent findings in non-neoplastic ureter urothelium of erythrocyte Lea+b-, Lea-b+, and Lea-b- individuals, alterations in tumors, except eight from Lea-b- individuals, were quantified on a scale from 0 (normal) to 3 (total loss). Scores were related to the pathologic stage and grade (P less than 0.01), and, in stage Pa tumors, to the clinical course: recurrence rate (P less than 0.10), stroma invasive recurrence, and/or papillomatosis (P less than 0.05). Although further studies are needed the current study points to Lewis a antigen determination as an advantageous prognostic tool in stage Pa tumors of the urinary bladder of Lea-b+ and Lea+b- individuals, who, together, constitute 94% of the population.     

Human bladder cancer associated antigens: evaluation of antigenicity in TCC tissues of different grades and in normal urothelium

The expression of five antigens, associated with transitional cell carcinoma (TCC) of the urinary bladder on biopsies of tumors or normal urothelium, was studied by immunostaining with the corresponding monoclonal antibodies. Both tissue sections and single cell preparations were investigated with either indirect immunoperoxidase staining or immunofluorescence. All 5 antigens were expressed on the majority (70-90%) of sectioned tumor specimens from 44 TCC patients, and 4 of them were similarly expressed on single cell tumor preparations from 26 additional patients. However, in both types of preparation, the degree of expression of these antigens varied from scattered staining of less than 25% of the tumor cells to homogenous staining of all or almost all cells. This degree of expression varied individually for each of the antigens and was not related to the malignancy grade of the tumors. However, as most of the tumors were of grades II or III, no conclusions regarding the relationship of antigen expression to the aggressiveness of the tumors can be drawn. In any event, all tumors expressed at least one and mostly several of these antigens. Antigen expression on biopsies of normal bladder mucosa from TCC patients or on urothelial biopsies from patients with prostate hyperplasia was also observed on single cell specimens (34 patients) but not on sectioned material (9 patients). However, the frequency of positive specimens was much lower (4-20%). Moreover, the number of cells expressing one or, occasionally, several of the antigens in normal urothelium was small (usually less than 5%). Because of these marked differences in antigen expression between tumors and normal tissue, the results indicate that a combination of 3-5 of the antibodies used in this study may be suitable for diagnostic purposes.     

Altered antigen expression predicts outcome in squamous cell carcinoma of the head and neck

Monoclonal antibody UM-A9 identifies an antigen found on the basal surface of epithelial cells and expressed on all of the squamous cell carcinomas (SCC) that we have tested. In a previous study, we showed that cell lines from metastatic or recurrent SCC exhibit stronger expression of the A9 cell membrane antigen than cell lines from the primary tumor of the same donors, suggesting that this marker is associated with tumor progression. Loss of expression in tumor tissue of normal A, B, and H (ABH) blood group antigens has also been linked to clinical behavior in some epithelial cancers. To determine the prognostic significance of these antigen markers, we prospectively evaluated tissue specimens for expression of these markers in a group of 82 consecutive, previously untreated patients with SCC of the head and neck. Three patterns corresponding to strong (pattern 1), intermediate (pattern 2), or weak (pattern 3) A9 antigen expression were observed. Fifty-eight percent of the patients whose tumors had pattern 1 A9 antigen expression and 78% of the patients with loss of blood group antigen had early relapse, compared with only 34% of those with A9 antigen pattern 2 or 3 (P = .042) and 37% of those whose tumors expressed the mature ABH blood group antigen (P = .012). The combination of A9 pattern and ABH blood group antigen expression in tumor tissue was the variable most strongly associated with duration of disease-free survival, even after adjustment for the traditional prognostic factors of tumor site, stage, and TNM classification. Loss of blood group was the most significant single variable associated with early recurrence, but among patients whose tumors retained ABH blood group antigen expression, the A9 pattern distinguished good and poor prognostic groups. To our knowledge, our study is the first to demonstrate that differences in blood group antigen expression are significantly correlated with disease-free survival in SCC of the head and neck. We have initiated a study (a) to determine the relationship of the A9 antigen and the blood group antigens with clinical response of the tumors and (b) to determine whether these markers should be used as prognostic indicators.     

The expression of ABH and Y blood group antigens in benign and malignant breast tissue: the preservation of the H and Y antigens in malignant epithelium

The ABO(H) and Y antigen status of epithelial cells from 45 breast carcinomas, 14 benign breast lesions and 7 normal breasts have been assessed using an indirect immunoperoxidase histochemical assay and a series of blood group specific monoclonal antibodies. All 20 A, AB and B group tumours had lost the A and B isoantigens, 13 of these tumours were however found to express H and Y antigens. Of 25 group O tumours 17 expressed the expected H and Y antigens. These findings were not dependent on the histological nature or the invasive characteristics of the tumour. Similar results were obtained when 28 metastases from breast carcinomas were examined, the H and Y antigens being identified in the tumour elements in 24 lymph nodes while we failed to identify either the A or B antigens. The development of breast malignancy appeared therefore to correlate best with the deletion of A and B glycosyl transferases. Normal breast tissue consistently expressed the expected blood group isoantigens. Areas of benign breast disease showed a more varied pattern of antigen expression. Seven of 14 lesions lacked ABH antigens, the loss of blood group structures could not however be correlated with any specific histological features and was not limited to the loss of A and B substances.     

ABO (H) cell surface antigens in benign and malignant parotid neoplasms

Twenty-two inflammatory, benign, or malignant parotid lesions were studied by means of the specific red cell adherence test (SRCA), a modification of the Coombs' mixed cell agglutination reaction. In 22 normal parotid tissues the acinar structures were devoid of red cell agglutination, but it was present in ductal epithelium. Findings were similar in 2 cases of parotitis, 11 benign mixed tumors, and 1 malignant mixed tumor. All lacked red cell agglutination in areas of neoplastic change. Benign Warthin's tumors (4 cases) demonstrated antigenicity in the columnar epithelial component of the tumor, but lacked red cell agglutination in areas of the lymphoid component. One malignant Warthin's tumor showed agglutination in areas of normal columnar epithelium but not in areas of malignant dedifferentiation. Undifferentiated carcinoma (1 case) and adenoid cystic carcinoma (2 cases) did not possess detectable ABO (H) antigens in neoplastic areas of the gland. The absence of ABO antigens in normal acinar glands supports their suggested myoepithelial or mesenchymal derivation, as the absence of antigen in benign and malignant mixed tumors supports their proposed mesenchymal derivation. Ductular epithelium and the epithelial components of benign Warthin's tumors have ABO (H) antigens, while the loss of antigen in the epithelial portion of the malignant Warthin's tumor is characteristic of epithelial neoplastic dedifferentiation. Loss of antigen in adenoid cystic and undifferentiated carcinomas of the parotid supports the concept that antigen is absent in epithelially derived malignant neoplasms.     

Cell surface antigens of human bladder tumors: definition of tumor subsets by monoclonal antibodies and correlation with growth characteristics

Normal human urothelium and tumors of urothelial origin were analyzed with a panel of seven mouse monoclonal antibodies that identify surface antigens of cultured bladder cancer cell lines. Three categories of antigens were defined on the basis of differential expression on normal urothelium versus bladder tumors. Om5 (a category 1 antigen) is a highly restricted, differentiation antigen detected in the normal urothelium of 50-60% individuals. No other normal cell type in Om5- or Om5+ individuals expresses Om5. The incidence of Om5 expression in superficial bladder tumors is significantly higher (88%) than in normal urothelium, whereas its expression in invasive or metastatic tumors is far lower (20%), suggesting Om5 gain/loss in bladder tumors. Paired biopsies of normal urothelium and bladder tumors from the same individuals have shown Om5 induction in the superficial bladder tumors of Om5- individuals and Om5 loss in invasive bladder cancers of Om5+ individuals. Category 2 antigens (T43, T138, T23) are not expressed by normal urothelium or most superficial bladder tumors but are detected on a high proportion of invasive or metastatic bladder tumors, indicating that category 2 antigens are associated with late stages of tumor progression. Category 3 antigens (T16, T87, J143) provide lineage markers for normal or neoplastic cells of urothelial origin, being found on normal urothelium and virtually all bladder tumors. Thus, differential expression of category 1 and 2 antigens divide bladder tumors into distinct subsets, and these subsets correlate with pathological and clinical features of the disease.     

High Expression of Human Uroplakin Ia in Urinary Bladder Transitional Cell Carcinoma

Uroplakins (UPs) Ia, Ib, II, and III are tissue-specific and differentiation-dependent transmem-brane proteins of the urothelium. We assessed the usefulness of human UP Ia as a histological marker by examining its expression in urinary bladder transitional cell carcinoma (TCC). A polyclonal antibody against human UP Ia was raised using a synthesized polypeptide. We applied our antibody to various organ tissues, including urothelium, and observed no crossreactivity. Analysis by RT-PCR of normal urothelium, TCC and other organ tissues indicated that the human UP Ia gene expression is highly specialized to urothelium, and is conserved in TCC. Using immunohistochemistry, we investigated the expression of UP Ia in TCC from patients who had undergone radical cystectomy and from autopsy cases. Positive staining (10% or more positive cancer cells) was noted in primary lesions from 61 of 63 (96.8%) cystectomy patients. Depending on pathological grade, high expression (50% or more positive cancer cells) was observed in 17 of 18 (94.4%) moderately- to well-differentiated TCC and in 36 of 45 (80.0%) poorly differentiated TCC. With regard to tumor invasion, high expression was noted in 20 of 22 (90.9%) superficial and 33 of 41 (80.5%) muscle-invasive TCC. Cause-specific survival rates were 68.6% and 75.0% in high- and low-expression patients, respectively (log-rank test, P =0.855, mean follow-up; 65.0 months). In metastases, positive reactions were observed in 13 of 18 (72.2%) lesions. UP Ia may represent a specific histological marker judging from the stable expression, although its value as a prognostic factor remains undetermined.     

High expression of human uroplakin Ia in urinary bladder transitional cell carcinoma.

Uroplakins (UPs) Ia, Ib, II, and III are tissue-specific and differentiation-dependent transmembrane proteins of the urothelium. We assessed the usefulness of human UP Ia as a histological marker by examining its expression in urinary bladder transitional cell carcinoma (TCC). A polyclonal antibody against human UP Ia was raised using a synthesized polypeptide. We applied our antibody to various organ tissues, including urothelium, and observed no crossreactivity. Analysis by RT-PCR of normal urothelium, TCC and other organ tissues indicated that the human UP Ia gene expression is highly specialized to urothelium, and is conserved in TCC. Using immunohistochemistry, we investigated the expression of UP Ia in TCC from patients who had undergone radical cystectomy and from autopsy cases. Positive staining (10% or more positive cancer cells) was noted in primary lesions from 61 of 63 (96.8%) cystectomy patients. Depending on pathological grade, high expression (50% or more positive cancer cells) was observed in 17 of 18 (94.4%) moderately- to well-differentiated TCC and in 36 of 45 (80.0%) poorly differentiated TCC. With regard to tumor invasion, high expression was noted in 20 of 22 (90.9%) superficial and 33 of 41 (80.5%) muscle-invasive TCC. Cause-specific survival rates were 68.6% and 75.0% in high- and low-expression patients, respectively (log-rank test, P = 0.855, mean follow-up; 65.0 months). In metastases, positive reactions were observed in 13 of 18 (72.2%) lesions. UP Ia may represent a specific histological marker judging from the stable expression, although its value as a prognostic factor remains undetermined.     

Overexpression of BDNF and TrkB in human bladder cancer specimens

BDNF (brain-derived neurotrophic factor) and TrkB (tropomyosin receptor kinase B) are expressed in several tumor types. However, the existence of BDNF and TrkB in human bladder cancer, especially transitional cell carcinoma (TCC), has not been established. In this study, commercial TCC tissue arrays were used. Slides of paraffin-fixed human bladder tissues included all grades of TCC (13, 30 and 22 tissue samples in grade I, II and III, respectively), superficial and invasive TCC (31 and 34 tissue samples, respectively), paired malignancy-uninvolved urothelium (35 tissue samples) and normal urothelial tissues (12 tissue samples). The intensities of BDNF and TrkB immunostaining were graded as background, mild and strong (score as 0, 1 and 2, respectively). The results showed significantly overexpressed BDNF and TrkB in TCC samples compared to normal urothelium. According to grade assignment of TCC samples, BDNF in grade III and TrkB in grade I and III appeared to be overexpressed. BDNF and TrkB were overexpressed in superficial TCC samples according to staging classification. The score between the paired TCC and its uninvolved urothelium was not statistically different. In conclusion, the existence of overexpressed BDNF and TrkB in human TCC has been demonstrated in our study. A strategy involving BDNF/TrkB blockade may be a new hope for TCC target therapy.     

Lewis system alterations in gastric carcinogenesis

Alterations in the expression of type 1 blood group-related antigens (Lewis a and b) were examined immunohistochemically in 371 consecutives gastric biopsy and 80 surgical specimens from patients of gastric carcinoma. The ABH and Lewis phenotype and secretor status of the patients were correlated with histologic findings. An anomalous expression of Lewis a antigen was found in 88 of 249 gastric biopsy specimens of Lewis (a-b+) phenotype patients. The prevalence of this anomaly increased with the evolution of the premalignant process, in agreement with the commonly accepted model of gastric carcinogenesis. Thus, anomalous Lewis a antigen appeared in 66.6% of gastric dysplasia cases, in 64.6% of intestinal metaplasia, in 15.4% of atrophic gastritis, and in 7.4% of superficial gastritis. No alterations were found in subjects with normal gastric mucosa. Forty-seven of the 49 Lewis (a-b+) phenotype gastric carcinoma patients showed antigenic alterations in tumor cells (anomalous Lewis a antigen in 36 and loss of Lewis antigens in 11). In 26 of these gastric specimens an anomalous Lewis a antigen was present in areas of intestinal metaplasia and/or dysplasia away from the area of neoplastic transformation. The expression of Lewis a antigen in Lewis (a-b+) phenotype patients is a frequent phenomenon in gastric neoplastic cells and could result from the blocked synthesis of Lewis b antigen with accumulation of its precursors. These findings suggest that, during gastric carcinogenesis, antigenic alterations may precede neoplastic transformation. An anomalous Lewis a antigen could constitute a significant index of severity of the histologic lesion and contribute to identifying high-risk individuals.     

Cancer-associated alterations of blood group antigen expression in human colorectal polyps

Human colorectal carcinoma tissues may exhibit several patterns of altered blood group substance (BGS) expression: reappearance of A, B, H, or Lewisb antigens in distal colon; deletion of BGS in the proximal colon with or without precursor substance accumulation; and incompatible BGS expression in proximal or distal colon. The present study evaluated these cancer-associated alterations in colorectal polyps with different malignant potential. With respect to ABH antigens, hyperplastic polyps (HPs), considered to have no malignant potential, did not exhibit incompatibility and only a few cases demonstrated BGS reappearance or deletion. Adenomatous polyps (APs) however, frequently reexpressed ABH antigens or expressed incompatible BG-A or B in 27% of polyps; one specimen demonstrated BG-B deletion. Precursor expression was not found in HPs but was frequently observed in APs. Reappearance of ABH in distal polyps was significantly correlated with increasing grade of dysplasia, but was not significantly correlated with polyp size or histological type. With respect to Lewis antigen expression, Lewisb reappearance occurred in almost every distal polyp, and Lewisa-Lewisb coexpression was also quite common. Lea deletion was frequently noted, especially in HP, but the significance of this finding is unclear. This study indicates that several antigenic alterations that occur in colorectal cancer tissues also appear in premalignant polyps, and often in early stages of the neoplastic process. The observation that incompatible expression of BG-A or B occurs only in AP and cancer tissues (as well as mucosa adjacent to cancer) but not in fetal colonic mucosa, adult normal colonic mucosa, or HP, suggests that this may be a cancer-specific phenomenon.     

Molecular analysis of transitional cell carcinoma using cDNA microarray

The incidence of transitional cell carcinoma (TCC), the fourth most common neoplasm diagnosed in men, is rising. Despite the development of several noninvasive diagnostic tests, none have gained full recognition by the clinicians. Gene expression profiling of tumors can identify new molecular markers for early diagnosis and disease follow-up. It also allows the classification of tumors into subclasses assisting in disease diagnosis and prognosis, as well as in treatment selection. In this paper, we employed expression profiling for molecular analysis of TCC. A TCC-derived cDNA microarray was constructed and hybridized with 19 probes from normal urothelium and TCC tissues. Hierarchical clustering analysis identified all normal urothelium samples to be tightly clustered and separated from the TCC samples, with 29 of the genes significantly induced (t-test, P<10(-5)) in noninvasive TCC compared to normal urothelium. The identified genes are involved in epithelial cells' functions, tumorigenesis or apoptosis, and could become molecular tools for noninvasive TCC diagnosis. Principal components analysis of the noninvasive and invasive TCC expression profiles further revealed sets of genes that are specifically induced in different tumor subsets, thus providing molecular fingerprints that expand the information gained from classical staging and grading.     

Blood group-related antigens in human germ cell tumors

With the use of immunohistochemical techniques, seven mouse monoclonal antibodies and the lectin from Ulex europaeus, detecting blood group antigens of the ABH and Lewis systems, have been used to define the distribution of these antigenic structures in germ cell tumors. The reagents used recognize the following blood group antigens: A, B, H, Lewisa, Lewisb, X (Lewisx), Y (Lewisy), and type I precursor antigen. Tumors from 29 patients were studied. Tumors studied consisted of pure embryonal carcinoma for eight patients, pure yolk sac tumor for two patients, embryonal carcinoma plus yolk sac tumor in one patient, and yolk sac tumor plus seminoma in one patient. Also studied were nine classic seminomas and a group of six patients with tumors classified as seminomas that exhibited atypical histological features. One patient had an anaplastic carcinoma arising from the mediastinum which could not be conclusively identified as a germ cell tumor morphologically and was analyzed separately. All embryonal carcinomas and yolk sac tumors exhibited strong positivity for type I precursor structure as detected by the K-21 monoclonal antibody. In marked contrast, there was non staining in classic seminomas but heterogeneous staining in five of six atypical seminomas. The majority of embryonal carcinomas and all yolk sac tumors studied demonstrated strong positivity for blood group antigen H. For seminoma, however, only one of the atypical cases and two of the classic cases (occasional cells) stained for H. Focal expression of the Y antigen was identified in 5 of 17 seminomas and in the majority of embryonal carcinomas and yolk sac tumors. Two yolk sac tumors and two classic seminomas expressed blood group X. The remaining blood group antigens were not expressed by seminomas while they were variably expressed by embryonal carcinoma and yolk sac tumors. These data suggest that K-21 and blood group antigen H may be distinguishing markers of nonseminomatous germ cell tumor versus seminoma. If so, it is possible that the heterogeneous expression of blood group substances in seminomas with atypical histologies is an indication of differentiation towards nonseminomatous germ cell tumor.