Isolation of complementary DNA encoding K-cadherin, a novel rat cadherin preferentially expressed in fetal kidney and kidney carcinoma

Complementary DNA for a novel member of the cadherin family, designated K-cadherin, was isolated from a rat renal cell carcinoma complementary DNA library by screening it with a short complementary DNA probe which was initially obtained from the RNA of day 16 fetal Wistar rat stomach mucosa by the polymerase chain reaction. The deduced primary structure of K-cadherin is 789 amino acid residues, which contain five internal repeats in its extracellular domain, a single putative transmembrane domain, and a cytoplasmic tail characteristic of those of classic type cadherins. K-cadherin exhibits low homology with mature proteins of mouse N- (38%), E- (35%), and P-cadherin (32%), and high homology with a partially identified human cadherin-6 protein (95%) at the amino acid level. Northern blot analysis revealed a high level of expression of K-cadherin mRNA in fetal rat kidney and brain, and rat kidney carcinoma with two major transcripts, 4.1 and 8.0 kilobases in size, whereas there was very weak or no expression in any organ of adult rats. The level of K-cadherin expression was also elevated in some human kidney cancer tissues. In the developing kidney, in situ hybridization showed localization of K-cadherin mRNA in the nephroblastic epithelial cells of comma bodies coinciding with those in the process of polarization during glomeruloneogenesis. These results demonstrate that K-cadherin must have important functions in both the process of kidney development and tumorigenesis of some types of kidney cancer.

Benign schwannoma of the esophagus: report of two cases with immunohistochemical and ultrastructural studies

Two cases of benign schwannoma of the esophagus are presented. The tumors were found in the thoracic esophagus of women of 56 and 64 years of age, respectively, who had complained of dysphagia and back pain. Tumorectomies were performed and the tumors were found to be located within the esophageal wall arising from the muscularis propria. The tumors were examined immunohistochemically and ultrastructurally. These tumors were identical in gross, histological and electron microscopic features. Grossly, the tumors showed yellowish-white cut surfaces without hemorrhage or necrosis. Microscopically, they were composed of spindle-shaped cells showing moderate variation in size and shape, and nuclear palisading. Lymphoid aggregates with germinal centers surrounded the tumors. Immunohistochemically, strong reactions for S-100 protein and neuron-specific enolase were observed in the cytoplasm of spindle cells, whereas reactions for muscle actin and desmin were negative. These findings, together with electron microscopic observations, supported the Schwann cell origin of these tumors.

[Breast sarcoidosis: 2 case reports and a review of 19 literature]

Case 1. A 40-year-old Japanese female with a 11 years history of sarcoidosis. Biopsy of a 0.5 cm-sized right breast nodule showed sarcoid granuloma. About two years later she had had bloody galactorrhoea and biopsy of an apparently normal site of the breast revealed periductal sarcoid granuloma and duct papillomatosis. Case 2. A 63-year-old Japanese female in whom biopsy of a 1 cm-sized right breast nodule revealed sarcoid granuloma. BHL, lung, eyes, muscle, lymph nodes and skin lesions were subsequently detected and the last two were histologically confirmed as sarcoidosis. After nine months all lesions disappeared. Some problems presented in the literature such as periductal sarcoid granuloma formation, latent sarcoidosis in the grossly normal breast and coexistent breast cancer are discussed briefly.

A 28 kDa-protein with disintegrin-like structure (jararhagin-C) purified from Bothrops jararaca venom inhibits collagen- and ADP-induced platelet aggregation

A 28 kDa-protein with inhibitory activity on collagen- and ADP-induced platelet aggregation was purified from the venom of the snake Bothrops jararaca. Its complete amino acid sequence corresponded to the carboxyl-terminal region consisting of disintegrin-like and cysteine-rich domains of jararhagin, a high molecular weight hemorrhagic metalloprotease. Sequence homology of the protein to other disintegrins and disintegrin-like proteins from various snake venoms is also presented.

Archaebacterial ether-linked lipid biosynthetic gene. Expression cloning, sequencing, and characterization of geranylgeranyl-diphosphate synthase

Archaebacterial Sulfolobus acidocaldarius geranylgeranyl-diphosphate (GGPP) synthase (EC 2.5.1.29) catalyzes consecutive condensations of isopentenyl diphosphate with allylic diphosphates to produce GGPP which is the important precursor of archaebacterial ether-linked lipids. We developed an expression screening method for cloning the GGPP synthase gene, which utilizes the carotenoid biosynthesis genes of Erwinia uredovora to visualize a clone expressing GGPP synthase, and then screened a genomic DNA library from S. acidocaldarius for the GGPP synthase gene by using this method. Positive clones were shown to contain GGPP synthase gene by the use of an in vitro assay. Extracts from Escherichia coli transformants catalyzed the condensation of isopentenyl diphosphate with farnesyl diphosphate (FPP) to produce (all-E)-GGPP. The nucleotide sequence of the 2.3-kilobase HindIII fragment of the cloned fragment was determined. This sequence specifies two open reading frames, ORF-1 and ORF-2. ORF-1 encodes GGPP synthase with the expected molecular weight of 36,873, and ORF-2 encodes a protein with homology for UDP-N-acetylglucosaminedolichyl phosphate N-acetylglucosaminephosphotransferase. The cloned GGPP synthase was partially purified with several chromatographies after heat treatment of cell free extract. This enzyme is extremely thermostable and has an optimal pH at 5.8. Dimethylallyl diphosphate, geranyl diphosphate, and (all-E)-FPP are, in decreasing order of activity, acceptable as allylic substrates to produce (all-E)-GGPP. When dimethylallyl diphosphate or geranyl diphosphate are the allylic substrates, a significant amount of mixture of the products is shorter than GGPP. (2Z,6E)-FPP is not a substrate. This enzyme recognizes the E-configuration of allylic substrate.

Growth-inhibition by hemin in K562 human leukemic cells is related to hemoglobin-producing activity

To determine the mechanism of the growth inhibition associated with the induction of erythroid differentiation in K562 cells by hemin, we used two K562 subclones with different hemoglobin (Hb)-producing activity. Hemin strongly inhibited the growth of K562-L, which had a low Hb-producing activity, but not that of K562-H, which had a high Hb-producing activity. When the cell growth of K562-L was inhibited by hemin, the S phase of the cell cycle decreased and the G2/M phase increased. In contrast, hemin had no effect on the cell cycle of K562-H. Without hemin treatment, the alpha-globin mRNA level was related to the degree of Hb production in K562-L and -H but the gamma-globin mRNA level was not. With hemin treatment, there was no increase in the alpha-globin mRNA level in K562-L but there was an increase in K562-H. The difference in alpha-globin mRNA levels correlated with the Hb production in K562-L and -H induced by hemin. The levels of c-myc and c-myb mRNAs in K562-L decreased when cell growth was strongly inhibited by hemin. These findings indicate that the growth inhibition of K562 cells by hemin is due to a suppression of the progression from the G0/G1 phase to the S phase and a delay in the G2/M phase, caused by the inhibition of c-myc and c-myb transcription. It is also affected by the Hb production, reflected in alpha-globin transcription.

Effects of intravenous infusion of dopamine on tumor blood flow in rat subcutis

To determine the effects of intravenous administration of dopamine hydrochloride (DA) on tumor blood flow (TBF), we measured the blood flow of normal subcutaneous tissue and subcutaneous tumor (LY-80, a variant of Yoshida sarcoma) in enflurane-anesthetized male Donryu rats using a hydrogen clearance method. Measurements were made before and during intravenous infusion of DA at a rate of 5 micrograms/kg/min, while recording the mean arterial blood pressure of the rats. Under mild hypertension induced by DA, the blood flow of normal subcutis decreased and TBF increased significantly. SCH-23390, an antagonist of the DA1 receptor, inhibited the enhancement of TBF by DA; while domperidone, an antagonist of the DA2 receptor, did not modify the effects of DA. In experimental chemotherapy against the tumor using adriamycin (ADM) 5 mg/kg i.v., only the combination of DA and ADM significantly inhibited the tumor growth. Moreover, DA reduced the weight loss caused by ADM. These results indicate that DA could have a role in increasing TBF and possibly enhance drug delivery to tumors. Moreover, it appears that the DA1 receptor contributes, at least in part, to the enhanced blood flow in rat subcutaneous tumor following DA administration.

Impaired hepatic copper homeostasis in Long-Evans Cinnamon rats: reduced biliary excretion of copper

To explain the pathogenesis of excessive copper accumulation in Long-Evans Cinnamon (LEC) rats, regarded as one of the animal models for hepatic-type Wilson's disease, we measured copper contents in liver tissue and bile, serum total copper concentration, and ceruloplamin oxidase activity in LEC rats before and after the onset of spontaneous hepatitis. The copper contents in liver tissue of both 11-wk-old and 18-mo-old LEC rats were about 60 times the amounts in age-matched Wistar and Long-Evans Agouti rats. The biliary copper excretion in 11-wk-old LEC rats was significantly lower than that of the Long-Evans Agouti and Wistar rats that were the same age (27.9 and 41.4%, respectively). In 18-mo-old LEC rats, biliary copper excretion was lower than that in the Long-Evans Agouti rats that were the same age, but the finding was statistically not significant. Serum copper and ceruloplasmin levels were markedly reduced in LEC rats of both ages. These findings suggest that LEC rats have similar defects of biliary copper excretion as observed in patients with Wilson's disease.

Assignment of disulfide bridges in the fusion glycoprotein of Sendai virus

The mature fusion (F) glycoprotein of the paramyxovirus family consists of two disulfide-linked subunits, the N-terminal F2 and the C-terminal F1 subunits, and contains 10 cysteine residues which are highly conserved at specific positions. The high level of conservation strongly suggests that they are indeed disulfide linked and play important roles in the folding and functioning of the molecule. However, it has not even been clarified which cysteine residues link the F2 and F1 subunits. This report describes our assignment of the disulfide bridges in purified Sendai virus F glycoprotein by fragmentation of the polypeptide and isolation of cystine-containing peptides and determination of their N-terminal sequences. The data demonstrate that all of the 10 cysteine residues participate in disulfide bridges and that Cys-70, the only cysteine in F2, and Cys-199, the most upstream cysteine in F1, form the interchain bond. Of the remaining eight cysteine residues clustered near the transmembrane domain of F1, the specific bridges identified are Cys-338 to Cys-347 and Cys-362 to Cys-370. Although no exact pairings between the subsequent four residues were defined, it seems likely that the most downstream, Cys-424, is linked to Cys-394, Cys-399, or Cys-401. Thus, we conclude that the cysteine-rich domain indeed contributes to the formation of a bunched structure containing at least two tandem cystine loops.

Antitumor and immunological activity of lentinan in comparison with LPS

Lentinan manifests marked antitumor and antimetastatic activity in numerous tumor/host systems, and prevents chemical and viral carcinogenesis. Modulation of immune or vascular functions by lentinan is involved in its antitumor effects. The impact of lentinan on the functions of macrophages is distinct from that of LPS. One of the effects of lentinan on the vascular system is the vascular dilatation and hemorrhage (VDH) reaction, and the effect can be monitored as augmented skin reactions to vasoactive mediators. Lentinan induces the VDH-like reaction at the tumor site, resulting in the induction of hemorrhagic necrosis and complete regression of the tumor. In contrast to LPS-induced tumor necrosis (Shwartzman's-like reaction), lentinan-induced tumor necrosis is T-cell dependent.

MR diagnosis of myelofibrosis

We present a case of secondary myelofibrosis in which magnetic resonance imaging (MRI) contributed to the diagnosis. On both T1- and T2-weighted images, bone marrow showed hypointensity. However, since blood transfusion therapy was performed prior to MRI, it was necessary to differentiate fibrosis from siderotic marrow. On gradient echo (GRASS) images, bone marrow also showed hypointensity, but not as prominent as that seen in siderotic marrow. After intravenous administration of gadolinium-dimethylene triaminepentaacetic acid (Gd-DTPA), enhancement of the marrow space may be induced by a fibrous change of the marrow. MR findings were confirmed by histological examination of the biopsy specimen.

Polyclonal B cell activation, endotoxin tolerance, and limulus tests of endotoxin preparations of some periodontopathogens

Potencies of polyclonal B-cell activation in C3H/HeN mice of Actinobacillus actinomycetemcomitans, Fusobacterium nucleatum, and Porphyromonas gingivalis endotoxins were 0.36, 0.13 and 0.04, taking Salmonella abortusequi as 1.0. F. nucleatum and P. gingivalis endotoxins showed positive reactions in C3H/HeJ mice. Most activities in C3H/HeN other than that of F. nucleatum were suppressed by polymyxin B. In C3H/HeJ mice, similar inhibitions were only 60% for P. gingivalis and hardly observed with F. nucleatum. The resistances to polymyxin B could be due to protein in the endotoxins. A promoting effect of T cells added to B cells was observed only in the activity of F. nucleatum endotoxin in C3H/HeJ mice; there was no influence in other groups. Test endotoxins had nearly the same ability to produce colony stimulating factor as did references and could not produce the factor in tolerant mice. The clinical significance of tolerance is discussed. Regression lines of endotoxin doses and limulus activities of test endotoxins and Salmonella were parallel, either in specific or non-specific tests. The lines of two test groups were also parallel; values obtained by two tests were very close. These data indicate that the test endotoxins did not contain (1-3)-beta-D-glucan and elicited qualitatively similar limulus reactions to that of the reference, despite their different chemical natures. In conclusion, these test preparations had an endotoxicity similar to that of the reference and contribute to produce periodontitis through polyclonal B cell activation.

[Pharmacokinetics of isosorbide dinitrate studied by the extrapolation model]

To make a pharmacokinetic model of isosorbide dinitrate (ISDN), we infused ISDN at 1, 10 or 30 micrograms.kg-1.min-1 into anesthetized rabbits and measured concentrations of ISDN and its metabolites (2-ISMN and 5-ISMN) in plasma, urine and bile. We found the concentration gradient of ISDN between arteries and veins and between the ascending aorta and femoral artery. These concentration gradients may occur due to metabolism and accumulation of ISDN in many organs and tissues, let alone the vascular endothelium. There was no significant difference in plasma concentrations of ISDN or its metabolites between the hepatic vein and femoral vein. It seems that ISDN is metabolized in various organs and tissues. By ISDN infusion of more than 10 micrograms.kg-1.min-1, the plasma concentration of ISDN showed a pronounced increase. It appears that there is metabolic saturation of ISDN. Using these informations, we extrapolated the model to human and the estimated values were compared with observed values to determine the validity of the extrapolation model. There was no remarkable differences between the estimated values and observed values. This suggests the validity of the model. The plasma concentrations of ISDN, estimated by this extrapolated model, showed a linear increase (Y = 30X) with the flow rate range of 0.2-5.0 micrograms.kg-1.min-1, when the metabolic rate was normal. With ISDN infusion of more than 5.0 micrograms.kg-1.min-1, the plasma concentrations of ISDN showed a pronounced increase. In the conditions of impaired metabolism, the plasma concentrations of ISDN increase exponentially.(ABSTRACT TRUNCATED AT 250 WORDS)

Antimetastatic effect of yeast mannan-bleomycin conjugate against mouse Lewis lung carcinoma

A conjugate of bleomycin (BLM) and the mannan of bakers' yeast (Saccharomyces cerevisiae wild type strain) (WNM) was synthesized. The assay of its antimetastatic effect on Lewis lung carcinoma (3LL) implanted in C57BL/6 mice showed that this conjugate exhibited a higher antimetastatic effect and longer life-span elongation than those of free bleomycin and mannan with corresponding doses. This conjugate was also found to kill the 3LL cells in vitro. 14C-Labeled mannan-bleomycin conjugate was much more bound than 14C-labeled dextran-bleomycin conjugate to the 3LL. It was concluded that the anti-cancer mechanism of this conjugate, WNM-BLM possessed a specific binding effect to the tumor cells and exhibited a cytocidal effect on the 3LL target cells.

Comparative study on alpha 1-adrenoceptor antagonist binding in human prostate and aorta

1. Specific binding of [3H]-prazosin in prostatic and aortic membranes of humans was saturable and of high affinity (prostate: apparent dissociation constant, Kd = 0.35 +/- 0.03 nmol/L; aorta: Kd = 0.26 +/- 0.03 nmol/L). The density of [3H]-prazosin binding sites (Bmax) for prostate and aorta was 546 +/- 31 and 61.6 +/- 1.6 fmol/mg protein, respectively. 2. Prazosin, YM617, naftopidil and urapidil competed with [3H]-prazosin for the binding sites in a dose-dependent manner in the prostate and aorta of humans. The binding affinities of these antagonists in both tissues were compared, based on the inhibition constant, Ki. Both prazosin and urapidil showed similar affinity to [3H]-prazosin binding sites in human tissue, whereas YM617 and naftopidil showed approximately a 12 and two times higher affinity, respectively, to alpha 1-adrenoceptor sites of prostate than aorta. 3. The chloroethylclonidine treatment reduced partially the Bmax values for specific [3H]-prazosin binding in the prostate and aorta of humans with little effect on the Kd values. 4. These data suggest that YM617 is a relatively selective antagonist of human prostatic alpha 1-adrenoceptors.

A framework for the DNA-protein recognition code of the probe helix in transcription factors: the chemical and stereochemical rules

BACKGROUND

Understanding the general mechanisms of sequence specific DNA recognition by proteins is a major challenge in structural biology. The existence of a 'DNA recognition code' for proteins, by which certain amino acid residues on a protein surface confer specificity for certain DNA bases, has been the subject of much discussion. However, no simple code has yet been established.

RESULTS

The principles of DNA recognition can be described at two levels. The 'chemical' rules describe the partnerships between amino acid side chains and DNA bases making favourable interactions in the major groove of DNA. Here I analyze the occurrence of nucleotide-amino acid contacts in previously determined crystal structures of DNA-protein complexes and find that simple rules pertain. I also describe 'stereochemical' rules for the probe helix type of DNA-binding motif found in certain transcription factors including leucine zipper and homeodomain proteins. These are a consequence of the binding geometry, and specify the amino acid and base positions used for the contacts, and the sizes of residues in the contact interface.

CONCLUSIONS

The chemical rules can be generalized for any DNA-binding motif, while the stereochemical rules are specific to a particular DNA-binding motif. The recognition code for a particular binding motif can be described by combining the two sets of rules.

DNA polymerase alpha overcomes an error-prone pause site in the presence of replication protein-A

Eukaryotic DNA polymerase alpha pauses at some sites on the natural DNA template of M13mp2. Terminal misincorporations of dA or dG, in place of dT, by DNA polymerase alpha have been reported to be within one of the pause sites, pause site II (positions 6269 and 6270 (Fry, M., and Loeb, L.A. (1992) Proc. Natl. Acad. Sci. U.S.A. 89, 763-767)). The DNA products arrested within pause site II (position 6270) were separated, annealed with synthetic templates, and further elongated by DNA polymerase alpha. It was confirmed that a considerable amount of terminal misincorporation of dG in place of dT occurred at this position. When M13mp2 DNA was coated with various amounts of replication protein-A (RP-A), however, DNA polymerase alpha was able to overcome the pause site II, whereas pause bands at other sites barely decreased. In contrast, Escherichia coli single-stranded DNA-binding protein did not specifically abolish the arrested band at pause site II, though it generally suppressed the reaction. Since RP-A hardly increased the elongation frequency from the primer carrying a 3'-mismatched terminal deoxynucleotide, the reduction of arrested products by RP-A may be attributed to the change in the incorporation mode from noncomplementary to complementary deoxynucleotides within pause site II and may not be due to the reinitiation from the mismatched 3'-terminal deoxynucleotide. To confirm this, we amplified the reaction products at pause site III by means of a polymerase chain reaction method and showed that the complementary strand to pause site II, which was elongated in the presence of RP-A, did not carry any detectable misinsertion. Therefore, the errorprone step of the DNA synthesis catalyzed by DNA polymerase alpha may be readily avoided by RP-A.

Solution structure of the DNA binding octapeptide repeat of the K10 gene product

A putative transcription factor, the Drosophila K10 gene product, contains eight repeats of the octapeptide sequence SPNQQQHP or close variants. The solution structure of the K10 repeat was studied by NMR using a peptide composed of two SPNQQQHP units (referred to here as HP2). To overcome problems caused by degeneracy of backbone amide signals of Gln residues, a series of synthetic peptides containing an 15N-labelled main chain amide at different positions in HP2 were synthesized. In aqueous trifluoroethanol solution, HP2 folds into two structural units; the SPNQ part of each unit folds into a turn structure, while the C-terminal part shows some helical characteristics but is less structured. The N-terminal turn is likely to provide a core that produces a more stable helical structure upon binding to DNA and probably 'caps' the segmented helical unit at its N-terminus. This model is supported by a DNA footprinting study which shows that one SPNQQQHP unit spans four base pairs upon binding to A/T-rich sequences of DNA.

Structure elucidation of glykenin glycosidic antibiotics from Basidiomycetes sp. V. High-performance liquid chromatographic separation of components of glykenin

The glycosidic antibiotics of the glykenin (GK) family produced by Basidiomycetes sp. were separated into nine components (GK-I-VII and DG) by normal-phase chromatography. It was found that these components differ in the number and location of the acetyl groups in the sugar moiety. Each component (GK-I-VII and DG) was further separated into three isomers (A, B and C), which possess different aglycones, by reversed-phase chromatography on an ODS column with methanol-acetonitrile as eluent. The best composition of the eluent was found to be methanol-acetonitrile-1% trifluoroacetic acid (4:3.5:2.5). The profile analysis of GK-III-VII and DG was also carried out using a modified mobile phase. The combination of normal- and reversed-phase chromatography separated all components of the GK mixture except GK-I and II. The relationship between structure and separation behaviour of GK is discussed.

Glucagon increases intracellular free calcium in a distal tubular cell line

Glucagon (Glu) influences renal tubular function and growth, although the signal transduction of Glu in the kidney still remains obscure. Rabbit cortical tubules were transformed by the pSV-neo3 gene to make a homogeneous cell colony, which responded to vasopressin but not to parathyroid hormone. The [Ca2+]i of the cells at the 9-10th passages was measured by the fluorescence indicator, fura-2. The [Ca2+]i was increased by Glu (10(-8) M) or bradykinin (10(-8) M), between which heterologous desensitization was observed. The Glu range of 10(-14) to 10(-6) M) significantly increased [Ca2+]i, while cAMP was not produced at any dose of Glu. Since the ranges of doses were from physiological to pharmacological, two concentrations of 10(-13) and 10(-8) M were employed to investigate the mechanisms. Glu at 10(-13) M led to a sustained rise in [Ca2+]i, which was completely blocked by external EGTA (5 mM, Ca-free solution). Glu at 10(-8) M provided a similar level of peak and sustained rise in [Ca2+]i, the sustained phase of which was blunted in Ca-free solution. Inositol tri/tetra phosphates were significantly increased by 10(-8) M, but not by 10(-13) M Glu. These data suggest that [Ca2+]i elevation is a major component of Glu-induced second messengers in the physiological and pharmacological range of doses of Glu, and that there might be two classes of pathways leading to increase in [Ca2+]i in transformed rabbit cortical collecting tubule cells.

Alteration of immunoreactivity by hydrated autoclaving, microwave treatment, and simple heating of paraffin-embedded tissue sections

The effects of treatment in a hydrated autoclave (121 degrees C, 2 atm for 20 min), microwave oven (in water), and simple heating (60 degrees C overnight in distilled water or 90 degrees C for 10 min in ZnSO4) on the stainability of 56 antigens by commercially available antibodies in formalin-fixed paraffin-embedded tissue sections were evaluated. The detectability of nuclear antigens, glycoprotein, lymphocytic surface markers, and chromogranin A was significantly and reproducibly improved by these treatments, whereas the detectability of viral antigens and peptide hormones was attenuated or unchanged. This enhancement includes not only the distinctiveness of the positive staining, but also the number of positive cells, as revealed by comparing serial sections. Among these four heating procedures, microwave heating and autoclaving were more effective than the others on p53, c-erbB-2, and CA125, whereas simple heating was best for smooth-muscle actin (HHF35 and CGA7). Generally the effects of the heating procedures for these antigens were consistent among the cases, but the effects on GFAP varied with the case. The alterations we observed could significantly influence the interpretation of immunohistochemical staining of currently popular tumor markers such as p53 in terms of their prevalence (28% vs 64% in gastric cancer; 36% vs 82% in metastatic liver cancer) and other diagnostically important markers.

Polymerase chain reaction-single strand conformation polymorphism analysis of the p53 gene in paraffin-embedded surgical material from human renal cell carcinomas

p53 tumour suppressor gene mutations were studied in 118 renal cell carcinomas using paraffin-embedded surgical material. Optimal results were obtained with analysis of exon lengths between 150 and 200 base pairs for polymerase chain reaction. Single strand conformation polymorphism and sequencing analysis revealed only two point mutations (2/118, 2%): one involving codon 135; TGC-->TTC (cysteine-->phenylalanine) and the other codon 175; CGC-->CAC (arginine-->histidine). Both of these cases were classified as granular cell subtype on microscopic observation. The data suggest that the p53 tumour suppressor gene is not related to tumour initiation, promotion, or progression of renal cell carcinomas. However, there is the possibility that granular cell type carcinomas may have a different genetic background from clear cell type renal neoplasms.