Gastric cancer in Colombia. IV. Nitrite and other ions in gastric contents of residents from a high-risk region.

Samples of gastric contents from 2 groups of patients from a region of high risk for gastric cancer were analyzed for pH, nitrite, nitrate, thiocyanate, and chloride. In each group, the patients could be divided into 2 subgroups: those with a gastric pH of less than 5 and those with a gastric pH of greater than 5. Above pH 5, nitrite was correlated with nitrate. The pH greater than 5 subgroups had significantly higher (P less than 0.01) nitrite content (20- to 100-fold). Some high- and low-nitrite samples were also analyzed for macro and trace metal ions, but differences were not significant. This is the first report in which patients with diagnosed gastric pathology related to a precancerous state were shown to have high levels of a putative carcinogen precursor. The results were compatible with our original hypothesis of intragastric nitrite formation by bacterial reduction of nitrate and concomitant synthesis of carcinogenic N-nitroso compounds.

Lectin-binding sites in preneoplastic and neoplastic lesions of human and rodent respiratory tracts.

The localization of fluorescein-labeled lectins, i.e., concanavalin A (Con A), Ricinus communis-120 (RCA), and wheat-germ agglutinin (WGA), were studied histologically in F344 rat epithelial lesions produced in the course of chemical carcinogenesis. WGA could not be demonstrated in these lesions. Although all lesions showed positive-binding sites when high concentrations of either Con A or RCA were used, a dilution study showed that the epithelial lesions had different affinities for lectins. With both Con A and RCA, dysplastic and neoplastic lesions showed the strongest intensity of fluorescence and squamous metaplasia showed the weakest. Normal and hyperplastic epithelia showed intermediate intensity. In the dilution study, RCA showed eight times more affinity and Con A showed two times more affinity for dysplastic and neoplastic epithelia than for normal or hyperplastic epithelium. Similar affinity patterns were observed in human lesions and tumors. With Con A, 58% of tumors showed much stronger fluorescence than did normal epithelium, and 44% of the tumors showed positive fluorescence with RCA. Although both lectins exhibited a stronger affinity for all the dysplastic-neoplastic lesions than for normal or hyperplastic epithelium, RCA proved to be the most adequate marker for preneoplastic lesions.

Mammary tumorigenesis in chemical carcinogen-treated mice. VII. Prolactin and progesterone levels in BALB/c mice.

PIP: Pituitary and serum levels of prolactin (PRL) and serum levels of progesterone (P) were determined by polyacrylamide gel electrophoresis and radioimmunoassays in BALB/c female mice, 15-17 or 44 weeks old, treated with chemical carcinogens. Neither 1.5 mg 3-methylcholanthrene (MCA) nor 1.5-6 mg 7,12-dimethylbenz(a)anthracene (DMBA) markedly altered pituitary or serum levels of PRL in the younger mice, though DMBA increased the total pituitary content of PRL by about 33% in the 44-week-old mice. However, this increase was not correlated with the incidence of mammary tumors in the group or individuals. MCA increased serum P levels by about 22% within 50 days of the last treatment. This increase was attributable to higher serum levels of P during the diestrous and proestrous phases of the cycle. Adrenalectomy reduced serum P levels by about 60%, wheras ovariectomy had no effect. Serum P levels in 44-week-old rats were not affected by DMBA. The results fail to support the notion that MCA and DMBA promote murine mammary tumorigenesis by increasing pituitary and serum prolactin concentrations.^ieng

Identification of 5-S-cysteinyldopa by high performance liquid chromatography in biopsies from patients with dysplastic melanocytic nevi.

The appearance of 5-[(L)-S-cysteinyl]dopa, a major product in pheomelanogenesis was examined in affected and nonaffected skins from 20 patients with clinical signs of dysplastic melanocytic nevi. Analysis by high performance liquid chromatography and electrochemical detection showed that 20 of the 35 lesions had a pathological formation of 5-[(L)-S-cysteinyl]dopa (0.04-28.86 ng/micrograms acid soluble protein). 5-[(L)-S-cysteinyl]dopa was not detected in any of the normal uninvolved skin samples analyzed.

Altered actin cytoskeletal patterns in two premalignant stages in human colon carcinoma development.

Primary culture of human colonic biopsies converts the single cell thick epithelial layer from a highly indented sheet in vivo into a flat patch on the surface of a Petri dish. Migration of cells from biopsies in a continuous sheet to form the patch cultures allows the cultured cells in large part to retain the junctional complexes and membrane interdigitations which connect adjacent cells in vivo and therefore to maintain their spatial relationships to neighboring cells. Migration of the cells onto a flat surface also allows visualization of their actin cables (E. Friedman, M. Verderame, S. Winawer, and R. Pollack, Cancer Res., 44: 3040-3050, 1984). Actin organization patterns have been studied in primary patch cultures of colonic epithelial cells from four stages in the development of colon cancer: normal tissue, normal-appearing but preneoplastic cells characteristic of familial polyposis patients, benign tumors or adenomas from familial polyposis patients, and benign and malignant tumors from patients in the general population. Carcinomas exhibited the least number of actin cables, while adenomas contained the greatest concentration. Similar actin patterns were seen in both familial polyposis and nonpolyposis adenomas. The preneoplastic prebenign tumor stage characteristic of familial polyposis patients had less actin cables than either normal cells or benign tumor cells. Thus actin organization loss characterized the transition from the normal colonic epithelial cell to the preneoplastic nontumor cell. The ability to form actin cables was then regained with the transition from the preneoplastic pretumor cell to the benign tumor cell and lost again with the benign tumor to malignant tumor transition. The complexity of these changes in actin organization during the step-wise transformation of colonic epithelial cells was not predicted from the simple model of actin cable loss accompanying fibroblast transformation.

Lack of albumin as genotypic marker of preneoplastic analbuminemic rat hepatocytes transplanted within albumin-positive liver.

In analbuminemic rats, preneoplastic hepatocytes lack the capability to produce albumin. On the other hand, the hepatocytes of F1 hybrids born from parents of analbuminemic rats and normal rats retain their capability to produce albumin, since the analbuminemia is inherited as a recessive trait in rats. We isolated hyperplastic nodule cells from Nagase's analbuminemic rats and transplanted them into the livers of F1 hybrid rats by infusion into the mesenteric vein. The host rats were subjected to a short term dietary 2-acetylaminofluorene and underwent a two-thirds partial hepatectomy to promote the growth of preneoplastic hepatocytes. Within 10 to 13 days after transplantation, may albumin-negative hepatocytic nodules were formed in the albumin-positive host livers. Almost all the albumin-negative nodules expressed conventional biochemical markers for preneoplastic hepatocytes. Eight to 9 weeks after the transplantation, almost the same number of albumin-negative nodules were observed as on days 10-13. However, roughly a half of the albumin-negative nodules showed no biochemical markers. The results indicate that the majority of early preneoplastic lesions revert to become phenotypically normal after removal of the promoting stimuli.

Cell lineages in liver carcinogenesis: possible clues from studies of the distribution of alpha-fetoprotein RNA sequences in cell populations isolated from normal, regenerating, and preneoplastic rat livers.

We analyzed in isolated rat liver cell populations and in fetal and neoplastic livers the distribution of RNA sequences which hybridize with alpha-fetoprotein (AFP) complementary DNA clones. Parenchymal and nonparenchymal cell populations were isolated from normal, regenerating, preneoplastic, and bile duct-ligated rat livers. We found that oval cells, fetal liver, and a primary hepatocellular carcinoma contain the full length 2.3-kilobase AFP messenger RNA (mRNA); in normal adult rat liver, 2.3-kilobase AFP mRNA is found at low levels in an unidentified subpopulation of nonparenchymal cells but is not detected in hepatocytes; both parenchymal and nonparenchymal cells from normal or preneoplastic livers contain in variable proportion a smaller AFP RNA which hybridizes only with complementary DNA clones containing sequences located near the 5' end of the rat AFP gene; during liver regeneration induced by CCl4, elevation of the full length AFP mRNA occurs in nonparenchymal cells but seemingly not in hepatocytes. The results suggest that some cells in the nonparenchymal cell fraction of normal adult rat liver might retain the capacity to produce the 2.3-kilobase AFP mRNA found in large amounts in fetal livers, oval cells, and hepatic tumors. Although the nature of these cells remains to be determined, we suggest that such cells might be the source of the small amounts of AFP synthesized in normal rat liver and may constitute the proposed but as yet uncharacterized "facultative stem cell" compartment in rat liver.

X-ray microanalysis of electrolyte content of normal, preneoplastic, and neoplastic mouse mammary tissue.

Intracellular sodium, chlorine, and potassium concentrations (mmol/kg dry weight) were determined by electron probe X-ray microanalysis of individual epithelial cells in freeze-dried 2-micrometer sections of mouse mammary tissue which were cut at -30 degrees. A model system was utilized in order to compare elemental content of cells from normal pregnant mammary tissue and preneoplastic and neoplastic mammary tissues from female BALB/cCrlMed mice. Animals were killed by cervical dislocation, and tissue was rapidly frozen in liquid propane. Normal mammary glands were obtained from primiparous mice at 16 to 17 days of gestation. Tissue from the hyperplastic alveolar nodule line D1 was removed from donor mice 12 to 16 weeks after transplantation into the cleared mammary fat pad. All mammary adenocarcinomas, D1T, were primary tumors which developed in mice with transplants of nodule line D1. Data were collected from five animals (10 cells/animal) in each of the three groups. It was found that the electrolyte content of cells of preneoplastic tissue was the same as that of the normal mammary tissue but was significantly elevated in neoplastic tissue (162, 130, and 48% increases for sodium, chlorine, and potassium, respectively). Thus, an increase in electrolyte content seems to be associated with the transformation to a neoplastic state and not associated with conversion to the preneoplastic state.

Expression of differentiation-specific proteins in preneoplastic mammary tissues in BALB/c mice.

The levels of milk-specific mRNAs (alpha-casein, whey acidic protein) and proteins (casein, alpha-lactalbumin) were examined in the DIM series of mammary preneoplastic outgrowth lines and tumors. The constitutive production of casein protein was variable among the preneoplastic DIM outgrowth lines maintained in virgin mice. Outgrowth line DIM-2 consistently expressed a very low level of casein mRNA and protein but no detectable alpha-lactalbumin protein. Outgrowth line DIM-4 expressed a high level of casein protein and no alpha-lactalbumin; however, by transplant generation 9, the levels of casein mRNA and protein were significantly decreased but remained greater than those found in DIM-2. Outgrowth line DIM-3 expressed high levels of casein protein during all transplant generations examined and sporadically exhibited detectable amounts of alpha-lactalbumin. The level of beta-casein mRNA in DIM-3 was 7 times greater than seen in DIM-4 outgrowths, but still only 2% of that measured in the normal mammary gland from lactating mice. The majority of tumors derived from the DIM outgrowth lines expressed very low levels of beta-casein mRNA and total casein protein, although occasionally tumors were observed with very high levels of casein expression. Immunoblot analysis of cellular extracts indicated that alpha, beta-, and gamma-caseins were expressed in the three outgrowth lines to varying degrees. Whey acidic protein mRNA attained barely detectable levels in the best of cases. Only outgrowth line DIM-3 responded to a normal lactogenic stimulus (lactating mouse) with significantly increased levels of milk-specific products. As determined by avidin-biotin peroxidase staining, the percentage of alveoli expressing beta-casein and alpha-lactalbumin proteins in lactating mice increased from 20 and 0%, respectively, in virgin mice to 85 and 40%, respectively, in lactating mice. Similarly, the levels of mRNA for beta-casein and whey acidic protein increased 8- and 5.5-fold, respectively. These results indicate that the cell populations selected by serial transplantation of preneoplastic mammary tissues fall into at least three categories with respect to expression of mammary-specific differentiation products: uninducible, inducible, constitutive. The DIM-3 outgrowth line appears to represent a highly inducible cell population. As concluded in earlier investigations, there was no correlation between secretory activity, morphology of the outgrowths, and tumor-producing capabilities in virgin mice. The effect of a normal lactogenic stimulus on the tumor potential of the DIM-3 line is currently under investigation.

Comparison of gene expression in preneoplastic and neoplastic rat liver to adult, fetal, regenerating, and tumor-promoted liver.

Computer-assisted analysis was performed on the in vitro translation products of polyadenylated RNA samples isolated from normal adult Fischer rat liver and from preneoplastic and neoplastic rat liver samples which were generated by the Solt Farber technique (Solt, D. and Farber, E., Nature 263:701-703, 1976). The vast majority of the differences in translation products observed throughout the progressive development of hepatocellular carcinoma was quantitative in nature. Importantly, this quantitative heterogeneity first became prevalent at the very early preneoplastic stage of hepatoma formation. Only 3 consistent qualitative alterations in translation products were observed to be associated with the hepatocarcinogenesis process. The appearance of two new polypeptides of molecular weight and isoelectric point of 32/5.2 and 43/5.1 appeared to be related to an early preneoplastic event in hepatoma development and the transition from a preneoplastic to a neoplastic state, respectively. Importantly, these new polypeptides were not observed in the in vitro translation products generated from fetal or regenerating liver samples or from liver samples which were chronically treated with phenobarbital or terachlorodibenzo-p-dioxin. One translation product (located at 35/6.6) of normal adult, fetal, and regenerating liver RNA samples was undetected in all preneoplastic, neoplastic, phenobarbital-, and terachlorodibenzo-p-dioxin-treated liver RNA translation products. The possibility exists that the specific loss of this gene product may promote the development of the transformed phenotype.

Early histological and functional alterations of ethionine liver carcinogenesis in rats fed a choline-deficient diet.

The effects of feeding a choline-deficient (CD) or a choline-supplemented diet upon the early stages of DL-ethionine carcinogenesis in rat liver were investigated. Low levels of DL-ethionine (0.05 and 0.10%) when fed with a CD diet were found to induce within 4 weeks a massive proliferation of oval cells without significant cell necrosis or presence of inflammatory cell infiltrates. The same levels of ethionine when fed with a choline-supplemented diet caused no significant histological alteration of the liver. In rats fed the CD plus ethionine diets concomitant with the proliferation of oval cells, there was a marked elevation in the content of alpha1-fetoprotein in both liver and plasma. After specific immunofluorescence staining, oval cells stained intensely for albumin and alpha1-fetoprotein. Hepatocytes stained only for albumin, and bile duct cells stained for neither albumin nor alpha1-fetoprotein. These results indicate that a diet deficient in choline markedly alters the response of rat liver to carcinogenetic doses of ethionine. Thus, ethionine hepatocarcinogenesis in rats fed a CD diet may be a useful model for the exploration of the mechanism(s) whereby a dietary factor influences hepatocarcinogenesis.

Epidermal ribosome accumulation during two-stage skin tumorigenesis.

The increase in interfollicular epidermal ribosomes on the backs of mice initiated with 7,12-dimethylbenz(a)-anthracene and promoted with 12-0-tetradecanoyl-phorbol-13-acetate was disproportionate to the increase in epidermal wet weight, protein, and DNA. Whereas ribosome numbers increased five- to sixfold 48 hr after the first, fourth, or eight application of 12-3-tetradecanoyl-phorbol-13-acetate, epidermal tissue increased only two- to threefold at these times. This disproportionate increase was due to the fact that, concurrent with the increased amount of interfollicular epidermal tissue and cells, ribosomes per g epidermis and per mg DNA increased two to three times normal. The tissue concentration and cellular content of ribosomes were also increased in the epidermal component of induced squamous papillomas. The work of others has demonstrated that, during growth of other tissues and organs, ribosome accumulation is proportionate to accumulation of tissue and/or cells. The results of our study indicate that the epidermis may have unique kinetics of ribosome accumulation during induced growth. Furthermore, these findings suggest the interesting possibility that other tumor-prone surface epithelia, such as the linings of the respiratory and gastrointestinal tracts, have similar kinetics of ribosome accumulation during induced growth.

Fecal diglycerides as selective endogenous mitogens for premalignant and malignant human colonic epithelial cells.

Diglycerides (DGs) have been found in fecal extracts at concentrations which induce mitogenesis of adenoma and some carcinoma cells but not normal cells in primary culture. DGs containing stearic, oleic, palmitic, and myristic acid side chains were found in fecal extracts from each of eight subjects. Synthetic 1,2-DGs, containing the fatty acids found in endogenous fecal DGs, induced mitogenesis in cultures of premalignant cells from each of 13 adenomas, covering all histological classes, and in cultures from two of four carcinomas. The potent adenoma mitogen, dimyristin, had no mitogenic activity on cultures of normal colonic epithelial cells from seven different subjects. These results suggest DGs may act as endogenous mitogens in the development of human colon cancer. The extent of adenoma mitogenesis was correlated with the chain length of the saturated R-groups: 16 greater than 14 greater than 12 greater than 10 greater than 8 much greater than 18. DGs with oleic acid residues, C18:1, were among the most active, while substitution of even one fatty acid residue with a stearic acid residue, C18:0, reduced or eliminated mitogenic activity. Dimyristin also induced enhanced levels of urokinase secretion from carcinoma cells, in parallel to the phorbol ester tumor promoter, 12-O-tetradecanoylphorbol-13-acetate. These results imply that DGs found in the colon induce a selective growth of benign colonic tumors and some carcinomas, and may enhance the invasive capacity of carcinomas, while leaving normal cells unaffected.

Immunocytochemical evaluation of human esophageal neoplasms and preneoplastic lesions for beta-chorionic gonadotropin, placental lactogen, alpha-fetoprotein, carcinoembryonic antigen, and nonspecific cross-reacting antigen.

Human esophageal neoplasms were studied in comparison to normal, uninvolved, and preneoplastic human esophageal epithelium for the presence of human chorionic gonadotropin (HCG), human placental lactogen (HPL), alpha-fetoprotein (AFP), carcinoembryonic antigen (CEA), and nonspecific cross-reacting antigen (NCA) using the unlabeled antibody peroxidase-antiperoxidase technique. HCG immunoreactivity was identified in 10 of 33 squamous cell carcinomas (33%), in 1 of 6 adenocarcinomas (17%), and 1 of 6 preneoplastic esophageal lesions (17%); while 9 of 33 squamous cell carcinomas (33%) and 1 of 6 adenocarcinomas (17%) contained immunoreactive AFP. Immunoreactive HPL was detected in 6 of 33 squamous cell carcinomas (20%), but in none of the adenocarcinomas. Neither AFP nor HPL immunoreactivity was identified in the 6 hyperplastic lesions which were studied. When stained with an antiserum that was able to detect both CEA and NCA, 27 of 33 squamous cell tumors (82%) and 6 of 6 adenocarcinomas (100%) showed positive immunostaining reactions. Of these, 8 squamous cell carcinomas and 1 adenocarcinoma were subsequently shown to contain only NCA immunoreactivity, while 19 squamous cell carcinomas and 5 adenocarcinomas contained both NCA and CEA immunoreactivity. NCA immunoreactivity alone was identified in 3 of 6 preneoplastic lesions and NCA and CEA immunoreactivity in 1 of 6 preneoplastic lesions. None of the markers was detected in 8 specimens of normal esophageal epithelium which were studied as controls, nor in 6 specimens of uninvolved esophageal epithelium obtained from patients with esophageal cancer. Most tumors expressed 2 or 3 markers, and some tumors were identified which expressed up to 4 of the 5 markers investigated. Only 3 tumors failed to express any of the markers studied. No association was found between the degree of tumor differentiation and presence or absence of HCG immunoreactivity. However, HPL immunoreactivity was more common in poorly differentiated squamous cell carcinomas. In contrast, immunoreactive AFP was more common in well-differentiated squamous cell carcinomas than in other tumor types. Similarly, both CEA and NCA were more frequently expressed in well-differentiated squamous cell carcinomas, adenosquamous carcinomas, and adenocarcinomas than in less differentiated tumors. Our results suggest that HCG, HPL, AFP, CEA, and NCA are tumor-associated antigens in esophageal cancer. Therefore, they could be of value in screening tests for esophageal neoplasms and could be useful in subclassification of esophageal neoplasms.

Expression of the c-erbB-2 gene product (p185) at different stages of neoplastic progression in the colon.

The c-erbB-2 gene has been found amplified in a number of human adenocarcinomas leading to elevated levels of expression of the p185 protein product. Increased expression of this putative growth factor receptor has been reported to occur by molecular mechanism other than gene amplification and for this reason we have studied the expression of the p185 protein in normal colon and in lesions representing different stages of neoplastic progression. We report amplification of the c-erbB-2 gene in 3 of 44 colon carcinomas and 1 of 5 preneoplastic polyps studied. Confirmation of expression of the p185 protein product was established in Western blot analysis and by immunocytochemical staining of tissue sections. An extended study, involving adenomatous polyps and carcinomatous material in immunostaining, revealed detectable presence of the p185 protein in 20% of carcinomas, consistent with immunoprecipitation data derived using established cell lines. In contrast, a high percentage of polyps showed strong staining with both p185 antibodies used, indicating elevated levels of expression of the c-erbB-2 protein associated with preneoplastic lesions. Staining of normal human colon revealed a restricted localization of this putative receptor to cells on the luminal colonic surface, with no expression in cells of the crypt. Histologically normal mucosa, adjacent to the tumor, showed a more extensive distribution involving the crypt suggestive of a disturbance in the normal expression of c-erbB-2. These results indicate that elevated expression of the c-erbB-2 protein is associated with early stages of colonic neoplasia but do not establish it as a primary factor in these events. The occurrence of multiple copies of the c-erbB-2 in a percentage of colon lesions, however, suggests a possible role for this gene in some colon malignancies.

Immunohistochemical demonstration of a mRNA-transport protein in rat liver putative preneoplastic foci.

A 65K protein, known for promoting nucleocytoplasmic mRNA transport in a cell-free system, was previously found in fetal and tumor cells of the rat. The primary objective of this study was to show specificity of immunohistochemical staining for the 65K protein in the livers of rats subjected to a hepatocarcinogenesis protocol. Altered hepatic foci were induced by feeding male weanling Sprague-Dawley rats 2-acetylaminofluorene (AAF) followed by a phenobarbital (PB) diet. It was shown, using polyclonal antibodies produced in rabbits, that the 65K protein was present in the cells of rat liver putative preneoplastic foci, with little or none being detected in the surrounding cells.

Cells of origin in human gastric neoplasms.

The epithelium of the surface mucosa of the human stomach is demonstrated to share an antigen (HP-DU-1) with human pancreatic ductal cell surface epithelium detectable by a murine monoclonal IgG. This marker was found to be characteristic of the epithelium of gastric surface mucosa and serves to distinguish these cells from the epithelium of gastric glands, the generative cell zone, the parietal and mucous neck cells. The absence of HP-DU-1 was confirmed in the epithelium of the small and large intestines, gall bladder, tracheobronchial trees, urinary bladder, intrahepatic bile ducts, prostatic and salivary glands. This surface marker was used to examine the participation of the surface mucosal cell in hyperplastic, pre-neoplastic and neoplastic lesions of the human gastric mucosa. Gastric hyperplastic polyps and polypoid hypertrophic gastritis were mainly composed of epithelium bearing HP-DU-1 antigens. In contrast epithelial cells of atrophic gastritis, atrophic gastritis with intestinal metaplasia, and adenocarcinoma of the stomach lacked this antigen.

Intestinal mucin antigens in ulcerative colitis and their relationship with malignancy.

The expression of two intestinal mucin-associated antigens large intestine mucin antigen (LIMA) and small intestine mucin antigen (SIMA) were investigated by indirect immunoperoxidase staining of rectal mucosa from patients suffering from ulcerative colitis with (n = 6) and without (n = 31) associated carcinoma and in noncolitic controls (n = 40). The aim was to assess the relationship between antigen patterns and malignant change. SIMA, which is localised predominantly in the small intestine, is virtually undetectable in the normal adult colonic mucosa. However, this antigen is present in the foetal colon and colonic carcinoma. LIMA is expressed in normal colonic mucosa, but absent from the small intestine. LIMA staining patterns were not significantly different among the three groups. In contrast, expression of SIMA was significantly higher in the patients who had developed carcinoma (6/6) than in the noncancer group (7/71) (P less than 0.001). The presence of SIMA was also significantly related to areas of dysplasia compared to normal (P = .03) or inflammation (P less than .05), but it did not differ from mucosa showing "indefinite" atypia. The finding of 31% SIMA-positive biopsies associated with severe inflammation in colitis with active disease, but no evidence of malignancy, is difficult to explain at the present stage. A followup study would be necessary to determine its significance. Perhaps the most important finding is the increased frequency of SIMA-positive foci in histologically normal mucosa in carcinoma patients compared with the noncancer group (P less than .001), suggesting a field change. These observations may be prove useful for the identification of patients who may be at risk of developing carcinoma.

Immunohistochemical evidence for impaired cell differentiation in the premalignant phase of prostate carcinogenesis.

Epithelial cell differentiation was evaluated in 15 samples of duct-acinar dysplasia, a putative premalignant lesion of the prostate, through immunohistochemical staining for five differentiation markers. Prostate-specific antigen (PSA), prostatic acid phosphatase (PAP), Leu-7, pepsinogen II (PG II), and tissue plasminogen activator (t-PA) are all constituents of seminal fluid that are produced by prostatic epithelium. Dysplasia foci were classified into three grades of severity and their locations mapped by camera lucida drawings of each slide. The degree of abnormal staining with each antibody was recorded on the map, and its correlation with dysplasia grade was evaluated. PSA, PAP, and Leu-7 staining were reduced in dysplasia and often absent in severe dysplasia, indicating that reduced differentiation is an early change in prostatic carcinogenesis. PG II and t-PA stains were sometimes positive in a region where they are usually absent, suggesting that deregulation of differentiation markers may accompany reduction in differentiation in these preneoplastic lesions.

Relation between gastric histology and gastric juice pH and nitrite and N-nitroso compound concentrations in the stomach after surgery for duodenal ulcer.

Formation of N-nitroso compounds in gastric juice has been implicated in the pathogenesis of cancer in the stomach after operation. Gastric juice was aspirated from 85 subjects: 23 were controls, 51 had previously undergone vagotomy and gastrojejunostomy, and 11 had previously undergone vagotomy and pyloroplasty. The gastric juice samples were analysed for pH, nitrite, and total N-nitroso compounds. A significant correlation was found between pH and nitrite concentration (p less than 0.01). No significant correlation was found between pH and total N-nitroso compound concentration or between nitrite and N-nitroso compound concentration. The vagotomy and gastrojejunostomy patients had higher pH values and higher concentrations of nitrites and N-nitroso compounds than controls (p = 0.01 in all cases). The 51 vagotomy and gastrojejunostomy patients also underwent endoscopy and biopsy. They were divided into three groups: group 1 (21 patients) had no intestinal metaplasia and no more than mild dysplasia; group 2 (20 patients) had intestinal metaplasia; and group 3 (10 patients) had moderate or severe dysplasia. Groups 2 and 3 both had higher pH values and higher nitrite concentrations than group 1 (p = 0.01 in all cases). There was no significant difference, however, between either group 2 or 3 and group 1 for total N-nitroso compound concentration. Since there was no simple linear relation between pH and N-nitroso compound concentration, it was concluded that formation of N-nitroso compounds at high pH was unlikely to be involved in the pathogenesis of gastric cancer in the hypochlorhydric stomach after operation. The relation between nitrite and histological abnormality was not associated with a similar relation between N-nitroso compounds and histological abnormality. It therefore appears that there is no simple relation between N-nitroso compounds and the pathogenesis of premalignant gastric mucosal changes.