[Expression of the tumormarker p16INK4a in cytology specimens of the urinary bladder. A new means for early recognition and surveillance of urothelial cancer]. / Vorkommen einer p16INK4a-Expression in Zytologien der Harnblase. Ein neuer Weg zur Früherkennung und Verlaufskontrolle beim Urothelkarzinom.

BACKGROUND: This study was carried out to learn whether cytological specimens from urinary bladder lavages express the tumor suppressor gene p16INK4a, whether an abnormally increased expression indicates a cancerous state and whether cytological measurements are comparable regarding sensitivity and specificity with measurements made in histological sections of biopsies. PATIENTS AND METHODS: A total of 82 urine specimens of patients suspected of having a bladder tumor were examined for the presence of p16INK4a. RESULTS: Out of 46 patients with urothelial carcinoma 29 expressed p16INK4a in the cells in the urine specimens. Out of 36 patients free of cancer 30 expressed no p16INK4a in cytological specimens. The sensitivity of the expression proved to be 63% and the specificity 83%. Well-differentiated carcinomas seldomly expressed an increased p16INK4a (sensitivity 27%), whereas moderately differentiated carcinomas showed a sensitivity of 69% and poorly differentiated carcinomas a sensitivity of 77%. CONCLUSION: Compared to other minimally invasive tumor markers, such as NMP22, the expression of p16INK4a in cytology specimens of urine appears to be a sensitive marker for urothelial carcinoma, especially for the detection of poorly differentiated carcinomas. Its high specificity makes it ideal for use in tumor screening.

[Opisthorchiasis simulating a malignancy]. / Die Opisthorchiasis in der Maske eines Malignoms.

We report on 2 patients from Siberia suffering from an infection with the parasite Opisthorchis felineus. The unusual course of their disease pretended in case 1 an eosinophilic leukemia and in case 2 a malignoma of the gallbladder. The Opisthorchiasis is endemic in large areas of Asia and Russia. Humans acquire the infection by eating raw fresh-water fish. Symptoms are nonspecific, but detection of eosinophilia in travellers or residents of endemic areas should induce analysis for specific antibodies against Opisthorchis species. Opisthorchiasis is known to be a precursor of cholangiocarcinoma. Malignoma which was initially suspected could be excluded in both cases and the patients were cured by oral administration of Praziquantel, 40-75 mg/kg body weight for 1 day in 3 divided doses.

Splenectomy for suspected malignant lymphoma in two patients with loiasis.

Intrasplenic lesions can cause diagnostic difficulties because malignant diseases can be excluded only by histologic examination. We present the cases of two patients with splenic manifestations of loiasis. Both patients had visited central Africa. Several years later, intrasplenic lesions were found during routine examinations (for chest trauma and employment, respectively). Both patients underwent splenectomies because malignant lymphoma was suspected. In both cases, histologic examination of the spleen showed eosinophilic granulomata with multiple Loa loa microfilariae.

[Blood group antigen expression in papillary carcinoma of the thyroid gland. An immunohistochemical and clinical study of expression of Lewis, ABO and related antigens]. / Blutgruppenantigenexpression in papillären Karzinomen der Schilddrüse. Eine immunhistochemische und klinische Studie über das Vorkommen von Lewis-, ABO- und verwandten Antigenen.

Nine monoclonal antibodies, lectin from Ulex europaeus and neuraminidase enzyme were employed to demonstrate the occurrence of type 1 and type 2 blood group antigens in 104 cases of papillary carcinoma of the thyroid. The reagents applied, recognize the following blood group related antigens: CA-50 (sialylated type 1 precursor), CA-19-9 (sialylated Le(a)), Le(a), Le(b), A, B, H, Le(x), sialylated Le(x), and Le(y). Immunohistochemical studies revealed that papillary carcinoma of the thyroid, in contrast to histologically normal thyroid tissue, is characterised by a progressive expression of blood group antigens. Most tumours (84%) reacted with C-50 antibody, whereas only a minority of the tissues demonstrated the CA-19-9 antigen (38%). Type 2 structures Le(x) (47%) and Le(y) (13%) were found less often than their corresponding type 1 isomers Le(a) (71%) and Le(b) (62%). Desialylation with neuraminidase increased the Le(a) and Le(x) staining intensity in 27 and 44 case, respectively. Of the A, B, H antigens the A determinants encountered most frequently (24%). Comparative examinations of sequential sections of the same tumour revealed coexpression of type 1 antigens in the same areas. In carcinomas showing type 1 and type 2 antigen reactivity, a complementary distribution of the structures in different tumour areas was often demonstrated. Some tumours presented combined type 1 and type 2 antigen expression in the same cells, however, in distinct areas within the cell. A follow-up examination was carried out in 68 of the 104 cases. The observation time ranged from 12 to 217 months. Thirteen patients suffered from recurrence, of which 7 died. While lymphatic metastases occurred in 39 tumours, distant metastases were detected in 6 patients. Most of the recurrences were found in patients with tumour classification pT4 (n = 19), whereas none of the pT1 carcinomas (n = 20) showed recurrence. The clinical results were compared to the blood group antigen expression results. There was no correlation between antigen expression and differentiation degree of the tumour. The pT4 tumours showed a significant higher expression of the CA-50, CA-19-9, Le(a) and Sialyl Le(x) structures. Carcinomas expressing the Le(y) antigen were associated with a significant higher level of metastasizing capacity. The Le(y), H type 1 and H type 2 antigens occurred more frequently in recurrent tumours (n = 14). In contrast, none of the patients whose carcinomas expressed the A-antigens (n = 14) suffered from a recurrence or hematogenous metastasis. Multiple stepwise regression analysis was carried out to check the importance of each staining and clinical factor. In this analysis, "distant metastasis' was the most important parameter, whereas the staining results were of minor statistical importance.

Quantitative lectin-histochemical and immunohistochemical studies on the occurrence of alpha(2,3)- and alpha(2,6)-linked sialic acid residues in colorectal carcinomas. Relation to clinicopathologic features.

BACKGROUND: Enhanced sialylation has been considered important for the metastatic growth of colorectal carcinomas. Using sequence- and sialic acid-specific lectins and a monoclonal antibody, the tumor-associated expression of alpha(2,3)- and alpha(2,6)-sialylated oligosaccharides was investigated. The study was designed to examine whether a random increase of sialylation or the expression of oligosaccharides carrying distinct sialic acid residues affect the biology of colorectal carcinomas. METHODS: Using computerized image analysis, formalin fixed and paraffin wax embedded specimens from 152 primary colorectal carcinomas were subjected to a quantitative analysis of the occurrence of sialoglycoconjugates detected by the maackia amurensis agglutinin (MAA: specific for alpha(2,3)-linked sialic acid residues), sambucus nigra agglutinin (SNA: specific for alpha(2,6)-linked sialic acid residues), and the monoclonal antibody B72.3 (MAB B72.3: specific for alpha(2,6)-N-acetyl-galactosamine-1-O-Ser/Thre). The data obtained by quantitating lectin/immunohistochemistry were related to morphologic and clinical parameters. RESULTS: Alpha(2,3)-linked sialic acid residues increased from Stage I to Stage II tumors but decreased in advanced carcinomas. Alpha(2,6)-sialylated glycoconjugates did not show any association with local tumor growth (depth of invasion). However, metastatic tumor growth was accompanied by a significant increase of alpha(2,6)-sialylated carbohydrate sequences. Univariate survival analysis revealed that the expression of SNA- and MAB B72.3-defined reactivity displayed an inverse relation to 5-year survival. Although more advanced tumor stage was associated with poor 5-year survival, tumors below the cutoff points for SNA- and MAB B72.3-defined reactivity indicated a better prognosis than the neoplasms above the cutoff points. In contrast, the expression of alpha(2,3)-linked sialic acid residues as detected by MAA had no significant effect on survival. Multivariate regression analysis revealed that SNA-reactivity, followed by tumor stage and the MAB B72.3-defined antigen reactivity were independent prognostic variables predicting overall survival, whereas MAA-reactivity, sex, age, histologic differentiation, and tumor grade had no independent prognostic value. The simultaneous expression of both sialyl-Tn- and SNA-reactivity determined tumors of high risk patients within the different tumor stages. CONCLUSIONS: Sequence-specific sialylation is associated with altered biologic behavior of colorectal carcinomas.

Expression of alpha-3/4-monofucosylated polylactosaminoglycan epitope, as defined by monoclonal antibody FW6, is a marker of the colorectal adenoma-carcinoma sequence.

BACKGROUND: The expression of a distinct alpha-3/4-monofucosylated polylactosaminoglycan epitope, which is detected by monoclonal antibody FW6, was investigated by comparative immunohistochemical analysis of colorectal tissue specimens exhibiting different grades of premalignant and malignant transformation. The presence of this peculiar epitope was compared with different lewis type 2 blood group antigens. METHODS: Paraffin embedded specimens from 8 hyperplastic polyps, 46 adenomas, 27 colorectal carcinomas, and 10 corresponding liver metastases were studied. Staining reactions included monoclonal antibodies FW6, AM-3 (anti-sialosyl-Le(x)), LeuM1 (anti-Le(x)), and 12-4LE (anti-Le(y)) in a standard peroxidase-antiperoxidase method. RESULTS: Hyperplastic polyps were not reactive with FW6 or LeuM1, but showed a slight binding of AM-3 and 12-4LE in some cases. Approximately two-thirds of the adenomatous polyps displayed a pronounced staining activity by AM-3, and approximately half of them revealed FW6, LeuM1, and 12-4LE binding. Only the expression of the FW6 (P < 0.005) epitope correlated with the presence of severe dysplasia. All antibodies were more or less reactive with colorectal carcinomas and their liver metastases, and some showed correlating binding patterns. CONCLUSIONS: FW6 revealed a high specificity for adenomas with areas of severe epithelial dysplasia. Because this monoclonal antibody also detects the great majority of carcinomas, it is reasonable to postulate that the alpha-3/4-monofucosylated polylactosaminoglycan epitope is an important marker for malignant transformation in the colorectal adenoma-carcinoma sequence.

Blood group antigen expression in malignant tumors of the thyroid: a parallel between medullary and nonmedullary carcinomas.

Blood group antigen (BGA) expression has been described in many fetal, adult, and tumorous tissues. Synthesis of BGA in the thyroid gland is regarded as oncofetal due to blood group structures that are detected in fetal and carcinomatous tissues but not in the normal adult organ. This study examined the prevalence of type 1 (CA-50, CA-19-9, Lea, Leb, A, B, H type 1) and type 2 (Le(x), Le(y), A, B, H type 2) antigens in normal thyroid (n = 25), papillary (n = 104), follicular (n = 52), anaplastic (n = 33), and medullary (n = 48) carcinomas of the thyroid. While normal thyroid tissue expressed no BGA, there was a significant increase of BGA expression in carcinomas of the thyroid gland. There are two theories about the possible origin of C cells, from which the medullary carcinomas arise. Some authors postulate that C cells belong to the amine precursor uptake and decarboxylation system and therefore derive from the neural crest, while others believe that C cells originate from the fifth pharyngeal pouch, as do the follicular cells. The results obtained in this study show that medullary and nonmedullary carcinomas correspond to one another in their BGA expression profile. Therefore it is concluded that medullary carcinomas may have the same origin as nonmedullary tumors of the thyroid.

Native and sialic acid masked Lewis(a) antigen reactivity in medullary thyroid carcinoma. Distinct tumour-associated and prognostic relevant antigens.

Forty-six medullary thyroid carcinomas (MTC) were subjected to a qualitative and quantitative characterization of native and sialic acid masked Lewis(a) (Le(a)) antigens. Immunohistochemical investigations included monoclonal antibodies (MABs) directed against alpha(2,3)-sialyl-Le(a), i.e. CA19-9 (MAB 19-9), native Le(a) (MAB anti Le(a)) and alpha(2,3)sialyl type 1 structure, i.e. CA 50 (MAB C50). To detect sialic acid masked Le(a) reactivity, MAB anti-Le(a) was also applied to native and enzymatically desialylated tissue sections with and without masking of sialic acid residues by sialic acid and sequence specific lectins. Only 7 MTC (15%) displayed a weak expression of CA19-9, while 16 (33%) showed moderate positive staining for native Le(a). Twenty-seven tumours exhibited a strong staining by the N'ase MAB anti Le(a) staining sequence. The latter could most effectively be inhibited by the simultaneous masking of alpha(2,3)-and alpha-(2,6)-linked sialic acid residues due to the competitive binding of sialic acid and sequence specific lectins: Maackia amurensis agglutinin (specific alpha(2,3)-linked sialic acid) and Sambucus nigra agglutinin (specific alpha(2,6)-linked sialic acid). Thus, in MTC the major portion of sialic acid masked Le(a) antigen reactivity is different from that detected by the MAB 19-9. The antigen reactivity is probably due to Le(a) structures containing both alpha(2,3) and alpha(2,6)-linked sialic acid residues. A highly significant correlation between the expression of CA50 and that detected by the N'ase MAB anti-Le(a) staining sequence indicates that the alpha(2,3)-sialyl type 1 chain represents a common intermediate structure within the pathway of the biosynthesis of sialylated Le(a) antigens, excluding the formation of CA19-9 via the formation of the disialyl type 1 structure. This is subsequently fucosylated to the corresponding sialic acid masked Le(a). Preliminary clinicopathological studies indicate that the sialic acid masked Le(a) antigens detected by the N'ase MAB anti-Le(a) staining sequence are related to biologically aggressive MTC.

Monoclonal antibody FW6 defines an epitope on alpha 3/4-monofucosylated polylactosaminoglycans expressed by fetal and colon carcinoma-associated mucins.

A mouse IgM monoclonal antibody FW6 was established after immunization of mice with mucins from human amniotic fluid and was characterized with regard to its binding epitope. According to a series of biochemical criteria the epitope is located on O-linked neutral carbohydrates of M(r) 700,000 and M(r) 570,000 mucins in human amniotic fluid. The epitope is presumed to contain alpha 3/4-linked fucose and terminal beta 3/4-linked galactose that are labile to the fucosidase I from almond emulsion or to the galactosidase from bovine testes, respectively. Immunoreactive fractions of glycan alditols from human amniotic fluid mucins were partially characterized by fast atom bombardment-mass spectrometry and methylation analysis to be composed of monofucosylated polylactosamine-type deca- or nonasaccharides. According to antibody competition studies, inhibition assays with defined carbohydrates and binding assays on neoglycolipids monoclonal antibody FW6 are presumed to recognize a novel epitope that is distinct from known carbohydrate markers of the Lex/Ley family associated with colonic carcinomas. The selective reactivity of this monoclonal antibody to the majority of human colonic carcinomas and its nonreactivity to normal colonic mucosa may render this antibody as a valuable tool in cancer diagnosis or cancer treatment.

Monoclonal antibody FW6 generated against a mucin-carbohydrate of human amniotic fluid recognises a colonic tumour-associated epitope.

Mucus glycoproteins of human amniotic fluid were used to generate a monoclonal antibody (MAb) FW6, which stained the intestine of a 24 week stage fetus. In adults, 76% of colonic adenocarcinomas (13/17) showed strong expression of the FW6 epitope, but it was not detected in the histologically normal mucosae adjacent to the tumours or in normal left colon mucosa. In addition, MAb FW6 stained large cell carcinomas of the lung (2/3), gastric carcinomas (5/11), and ovary adenocarcinomas (3/4). The expression in carcinomas can also be called ectopic for testing normal tissues. MAb FW6 was also reactive with pyloric mucus glands, Brunner's glands of the duodenum, Paneth cells of the ileum, pancreatic ducts, absorptive cells of the right colon, bronchiolar glands, kidney urothelia, and with a restricted number of normal mucinous tubuli of salivary gland. It was demonstrated to be under the control of the secretion gene only in intestinal Paneth cells and absorptive cells of the right colon. Comparative histochemical analysis comprising a panel of MAbs suggests that the corresponding epitope of the MAb FW6 is a type II chain related carbohydrate structure belonging to the Lex/Ley-antigen family, but is different from short chain Lex and Ley.

Blood group antigen expression in medullary carcinoma of the thyroid. An immunohistochemical study on the occurrence of type 1 chain-derived antigens.

Using monoclonal antibodies (MoABs) against blood group determinants and related carbohydrate sequences, it is now possible to clarify their carcinoma-associated modulation at a molecular level. In the present study a panel of MoABs against different type 1 chain derived blood group antigens, comprising A, B, H type 1, Le(a), sialyl-Le(a) (CA 19-9), sialyl type 1 structure (CA 50), and Le(b) was used to investigate their immunoreactivity in 38 medullary carcinomas of the thyroid (MTC) and in normal thyroid tissue. The antigens were not expressed in normal follicular or C-cells but were expressed to a various extent in MTC. The studies revealed some characteristic anomalies in the frequency and patterns of tumor-associated antigen expression. The MoAB C 50 stained 32 of the 38 tumors, H type 1 (Le(d)) was demonstrated in 21 and the Le(b) antigen in 27. The Le(a)- and the A antigen were detected in 10 and 12 tumors and the B antigen in one. From the results some rules about the pathways for tumor-associated re-expression of these antigens can be deduced. Le(a) antigen expression was significantly correlated with the CA 50 and Le(b) antigens. The significant relation observed between A-, H1-, and Le(b) antigen formation in MTC suggests the existence of a carcinoma-associated fucosyltransferase committing the type 1 precursor chain along the H1-antigen pathway, and by further glycosylation to an A-, B-, or a Le(b) antigen. Comparative studies of tumor-associated H type 1 and H type 2 antigen expression revealed that H type 2 antigen synthesis was significantly related to a blood type 0 in the host. On the other hand, H1 antigen reactivity was independent of the AB0 blood type of the hosts and was also detected in H type 2 antigen-negative tumors. These findings support the proposal that even in tumor tissue, H antigen expression is still determined by the interaction of at least two different genes. Despite the occurrence of the precursor substance (CA 50) and the formation of the Le(a)- and Le(b) antigens, indicating the presence of a alpha 1,4-fucosyl-transferase (Lewis-enzyme), only two tumors showed the formation of CA 19-9. In conclusion, the investigations demonstrated the dominant re-expression of three type 1 chain-derived structures in MTC, namely H type 1, Le(b), and CA 50. These findings support the general concept demonstrated in other carcinomas, that fucosyl- and sialyltransferases are preferentially activated in MTC.(ABSTRACT TRUNCATED AT 400 WORDS)

Enhancement of carcinoembryonic antigen (CEA) expression in colorectal tumors by neuraminidase.

Twelve colorectal carcinomas with transitional mucosa and 10 colorectal adenomas which previously displayed weak or no carcinoembryonic antigen (CEA) expression were selected to verify whether neuraminidase unmasks CEA carbohydrate epitopes and, consequently, enhances the CEA expression. Peroxidase-antiperoxidase (PAP) method was performed on routinely processed tissues, without and with neuraminidase pretreatment of the sections. Lysine, without and with neuraminidase pretreatment of the sections. Lysine, as a modifier of electrostatic charge at cell surface, instead of neuraminidase was used to clarify whether the enzyme yields a specific or non-specific influence on CEA expression. All colorectal tumors exhibited more CEA after neuraminidase pretreatment, while previous negative specimens developed CEA expression. The same effect was observed in some transitional mucosa sections. This has not occurred in normal mucosa, probably owing to a resistant sialylation. The enhancement effect of lysine, although more weakly and not entirely superimposed to that or neuraminidase, suggests non-specific mechanisms of enzyme action. The removal of the negative charge at cell surface, especially due to sialic acid, allows more anti-CEA antibodies to react. The neuraminidase pretreatment of the sections is a useful method to demonstrate the real incidence of CEA in the colorectal tumors.

Histochemical reactivity of the Geodia cydonium agglutinin (GCA) in human tissues.

We applied a peroxidase-antiperoxidase technique to study the distribution pattern and binding characteristics of the lectin from the marine sponge Geodia cydonium (Geodia cydonium agglutinin; GCA) in various human tissues. This lectin has been shown to possess a broad reactivity, but there was a distinct distribution of binding sites within the different organs. In the histochemical system GCA displayed no blood group specificity and labeled red blood cells, the vascular endothelium, and epithelial cells showing blood group antigen expression independent of the ABH blood group status. However, inhibition of GCA reactivity by simple sugars and complex carbohydrates demonstrated tissue-specific differences of lectin binding related to the ABH blood group status of the tissue and revealed information on the structural requirements of the histological lectin binding site. Tissues that totally lacked blood group antigens or that expressed only the H-antigen disclosed a GCA reactivity which was completely inhibited by lactose. In contrast, tissues that expressed blood group A- or blood group B-antigen exhibited a lactose-resistant lectin binding which was inhibited only by water-soluble blood group substance A from peptone A and by bovine glycophorin but not by other complex carbohydrates, including human glycophorin and human asialoglycophorin. Competitive inhibition studies in situ revealed that GCA binding was not inhibited by blood group type I/II carbohydrate sequence-specific lectins or by lectins with other sugar specificities. Inhibition by lactose of GCA binding to some histological sites indicates that the binding site consists of a beta-linked galactose-containing disaccharide. However, periodate oxidation of tissue sections had no effect on lectin binding, pointing to a subterminal location of the relevant sequence. The results obtained from inhibition studies with simple saccharides and complex carbohydrates in relation to the expression of ABH blood group antigens suggest a complex lectin combining site(s) in histological specimens. The lectin may possess either one binding site with a range of affinities for different carbohydrates (besides beta-linked disaccharides the GCA binding site accommodates to carbohydrate determinants carrying the blood group A or blood group B determinant), or may possess two different binding sites. Besides an acceptor site for beta-linked disaccharides, an additional binding site may exist accommodating to extended carbohydrate sequences related to A or B blood group structures. In conclusion, GCA represents a blood group-nonspecific lectin whose binding affinities are determined by the ABH blood group status of the tissue.

Antigen CA 19-9: presence in mucosa of nondiseased müllerian duct derivatives and marker for differentiation in their carcinomas.

CA 19-9, a side branch of the Lewis blood group system, is a sialylated Lewis A antigen that is highly expressed by many adenocarcinomas of the digestive tract. The müllerian duct-derived mucosa of the uterus and fallopian tubes also synthesizes Lewis blood group antigens. To test whether the expression of CA 19-9 is enhanced in carcinomas of müllerian duct origin, we performed immunohistochemical staining for CA 19-9 in normal tissues from 33 women and in adenocarcinomas from 88 patients. In the normal uterine cervix, CA 19-9 was expressed in the cytoplasm of scattered glandular cells in 26 of 29 specimens. It was observed in the apical regions of mucosal cells in six of 26 normal endometrial samples and two of 13 normal fallopian tube specimens. These results are consistent with the presence of antigen CA 19-9 on a secretory product of the nondiseased mucosa of the müllerian duct. In adenocarcinomas of the endocervix, endometrium, and fallopian tubes, CA 19-9 was found in seven of 11, 57 of 71, and five of six samples, respectively. Progressive loss of differentiation was accompanied by disruption of subcellular localization of CA 19-9 and its secretion toward the glandular lumina. In well-differentiated regions of tumors, the antigen was detected mainly at the luminal surface of cancerous glands, whereas the staining was mostly cytoplasmic or vacuolar in less differentiated areas. The degree of CA 19-9 expression was inversely related to tumor differentiation (P less than .001).

[Responders and non-responders of surfactant therapy of very small premature infants. A clinical, histopathologic and immunohistochemical analysis]. / Responder und Nonresponder in der Surfactanttherapie sehr kleiner Frühgeborener. Eine klinische, histopathologische und immunhistochemische Analyse.

The administration of surfactants is highly effective and yields an immediate clinical response in cases of a lack of surfactant in the premature lung of preterm infants. The administration of surfactants might diminish the need for intensive care and artificial ventilation thereby also reducing or preventing the severe side effects associated with these therapeutic measures. However, the lack of clear clinical features precludes a reliable predictive forecast of the therapeutic outcome. Only the therapeutic follow-up period can disclose possible damage due to the administration of surfactants. Histological preparations of lung specimens from non-responding infants reveal cellular inflammatory infiltrations, destruction of the alveolo-capillary basement membrane and monocytic phagocytosis.

Sialylated glycoconjugates in chromophobe cell renal carcinoma compared with other renal cell tumors. Indication of its development from the collecting duct epithelium.

The present study was designed to shed light on the extraordinary histochemical properties of the chromophobe cell renal carcinoma detected by Hale's colloidal iron reaction. Special emphasis was laid on the lectin histochemical analysis of cytoplasmic glycoconjugates. Binding of peanut agglutinin (PNA) and Erythrina cristagalli agglutinin (ECA) after enzymatic release of sialic acid and direct binding of Dolichos biflorus agglutinin (DBA) correlates well with the expression of binding sites for Sambucus nigra agglutinin (SNA) and Maackia amurensis agglutinin (MAA) revealing abundant sialylated carbohydrate moieties within the cytoplasm. This characteristic binding pattern differs considerably from the faint staining observed in the majority of other renal carcinomas, thus confirming that the chromophobe cell renal carcinoma is a distinct entity. However, the lectin binding pattern of renal oncocytoma obviously resembles that of chromophobe carcinoma indicating a close relationship between these renal tumors. Detailed analysis of adjacent renal parenchyma revealed a lectin binding pattern quite similar to that described in the chromophobe carcinomas exclusively in the intercalated cells lining the collecting duct. This finding suggests that the chromophobe cell renal carcinoma originates from the collecting duct epithelium. The detection of small complexes consisting of altered epithelia which display the morphological characteristics of chromophobe carcinoma and the histochemical properties of intercalated cells probably indicates the emergence of preneoplastic lesions preceding the development of chromophobe carcinoma. Even though further studies are clearly needed to elucidate the physiological role of the cellular glycoconjugates detected, the present results already provide valuable insight into the histogenesis and pathogenesis of the chromophobe cell renal carcinoma.