Is the ABCB1 gene associated with the increased risk of gastric cancer development?--preliminary research.

One of the most common malignant diseases, both worldwide and in Poland, is gastric cancer. The pathogenesis of gastric cancer development is not entirely clear. Next to the environmental risk factors, such as Helicobacter pylori infection or dietary habits, the host genetic factors as predispositions to gastric cancer development are discussed. A transmembrane protein that could be associated with predisposition to cancer development is P-glycoprotein (P-gp). Physiologically, P-gp is present in normal tissue of the gastrointestinal tract, where it plays a protective role by transporting xenobiotics from a cell into extracellular environment. P-gp is encoded by the highly polymorphic ABCB1 gene. The most frequent polymorphisms at positions 1236, 2677, and 3435 may affect both the function and amount of protein, thereby leading to a loss of its physiological function, which could increase the predisposition to development of many diseases, including cancer. In this study, the potential significance of the ABCB1 gene in the development and progression of gastric cancer was evaluated. In 19 tissue samples collected from patients with gastric cancer, the ABCB1 gene polymorphisms were identified at positions 1236 and 2677 by automated sequencing and SNP 3435 by the RFLP method. The relative level of ABCB1 expression was measured in 10 samples of gastric cancer and morphologically normal tissues by real-time PCR. For SNPs at positions 1236, 2677, and 3435, no statistically significant differences in genotype frequencies between gastric cancer patients and healthy individuals were found. However, genotype TT for all studied polymorphisms occurred more frequently in the group of gastric cancer patients (31.6, 26.3, 42.1%, respectively) than in the group of healthy individuals (14.6, 13.5, 21.9%, respectively). The lowest relative expression levels of ABCB1 mRNA were observed for genotypes CC of SNP 1236, CC of SNP 3435, and GG of SNP 2677 (median: 0.215, 0.160, 0.160, respectively). There was a tendency that mutant homozygote TT for SNPs at positions 1236, 2677, and 3435 occurred more frequently in the subgroup of patients with Tis or stage I of TNM classification (SNP 1236 p = 0.0760; SNP 2677 p = 0.0813; SNP 3435 p = 0.0760) than in the subgroup of patients with stage II or III. Also the expression levels were lowest (median 0.740) in the group of patients with the less advanced clinical stage of cancer (Tis or I). Preliminary research showed that the ABCB1 gene polymorphisms at positions 1236, 2677, and 3435 were not related to an increased susceptibility of gastric cancer development. However, they may be associated with the inhibition of gastric cancer progression.

Influence of antibiotic therapy on the level of selected angiogenic factors in patients with benign gynecologic tumors--preliminary report.

An increased fibrin level enhances the activity of proangiogenic factors and may contribute to tumor formation. Formation of new blood vessels during angiogenesis leads to neoplasm development through interaction with factors such as basic fibroblast growth factor (bFGF), vascular endothelial growth factor (VEGF) and interleukins. The aim of this study was to investigate the influence of perioperative antibiotic therapy in women with benign gynecological tumors with regard to basic fibroblast growth factor level, fibrinogen concentration and fibrin viscosity. The influence of clindamycin plus metronidazole therapy (group I) and cephazolin therapy (group II) on fibrinogen concentration, level of bFGF and fibrin viscosity was studied in women diagnosed with nonmalignant myomas and cysts. In patients with benign gynecologic tumors, higher bFGF levels (51.40 +/- 13.72 pg/ml), fibrinogen concentration (348.26 +/- 164.74 mg/dl) and fibrin viscosity (2.63 +/- 0.36 mPa) were observed, as compared with healthy women. There were strong indications that antiangiogenic activity occurred with both clindamycin plus metronidazole and cephazolin, although the response to these particular antibiotic therapies was different. The use of various drug therapies in groups I and II resulted in faster and delayed antiangiogenic effects, respectively. Further research is essential to provide more detailed information about the mechanisms of the induction of antiangiogenic activity by perioperative adjuvant antibiotic treatment.

Release kinetics of basic fibroblast growth factor (bFGF) from certain biopolymers in the presence of ketoprofen.

The aim of the present study was the evaluation of basic fibroblast growth factor (bFGF, FGF-2) release in vitro from four types of polymer bases (carriers), fibrin, microcrystalline chitosan (MCCh), fibrin and MCCh, as well as MCCh and methylcellulose (MC) in the presence or absence of ketoprofen (KTA). Amount of released basic fibroblast growth factor was measured immunoenzymatically using Elisa (R&D System). Ketoprofen concentration was determined spectrophoto-metrically at 255 nm, using an appropriate absorbance factor, alpha 1 cm (1%) = 662. The most significant influence of ketoprofen on bFGF release was seen in the case of microcrystalline chitosan carrier elution. Parameters of the equation which describe the amount of bFGF released from chitosan carrier with and without KTA are y = 6.842 +/- 1.637 In(t) + 14.935 +/- 2.378, determination coefficient, R2 = 0.9332 and y = 4.070 +/- 0.622 In(t) + 10.589 +/- 1.011, determination coefficient, R2 = 0.9606. The time after which 20% of bFGF was released (t 20%) in the presence of ketoprofen was 2.1 h whereas it was significantly longer without ketoprofen (10.1 h). The amount of bFGF released from fibrin carrier was lower in the presence of ketoprofen. The time taken for 20% of bFGF to be released (t 20%) was very long (41.7h) in the presence of KTA and 16.3 h. without KTA. The other carriers (fibrin + MCCh and MCCh + MC) in the presence of ketoprofen appear to have an insignificant influence on the kinetics of basic fibroblast growth factor release. For the chitosan carrier (p = 0.05, and also p = 0.01, when t(theoret) = 2.921), there is a statistically significant difference between the coefficients (a1 and a2) of the regression equation describing the process of basic fibroblast growth factor release from the base with and without ketoprofen. It was also found that the amount of ketoprofen released varied considerably according to the carrier. All results clearly indicate that the type of carrier not only has an impact on the amount of bFGF released, but also on the kinetics of ketoprofen release.

Targeted delivery of anti-cancer growth inhibitory peptides derived from human alpha-fetoprotein: review of an International Multi-Center Collaborative Study.

The alpha-fetoprotein derived growth inhibitory peptide (GIP) is a 34-amino acid peptide composed of three biologically active subfragments. GIP-34 and its three constituent segments have been synthesized, purified, and studied for biological activity. The GIP-34 and GIP-8 have been characterized as anticancer therapeutic peptides. An multicenter study was initiated to elucidate the means by which these peptide drugs could be targeted to tumor cells. The study first established which cancer types were specifically targeted by the GIP peptides in both in vitro and in vivo investigations. It was next demonstrated that radiolabeled peptide ((125)I GIP-34) is specifically localized to rodent breast tumors at 24 h post-injection. The radionuclide studies also provided evidence for a proposed cell surface receptor; this was confirmed in a further study using fluorescent-labeled GIP-nanobeads which localized at the plasma membrane of MCF-7 breast cancer cells. Finally, it was readily demonstrated that GIP conjugated to either fluorescein or doxorubicin (DOX) underwent tumor cell uptake; subsequently, DOX-GIP conjugates induced cytotoxic cell destruction indicating the utility of GIP segments as cancer therapeutic agents. Following a discussion of the preceding results, a candidate cell surface receptor family was proposed which correlated with previous published reports for a putative AFP/GIP receptor.

Maspin and Nm23-H1 expression in colorectal cancer.

The aim of the study was to analyze the expression of Nm23-H1 and maspin proteins in a series of colorectal adenocarcinoma and to assess their applicability as prognostic factors in this type of cancer. 102 specimens of colorectal carcinoma were analyzed by immunohistochemistry with the use of anti-Nm23-H1 and anti-maspin monoclonal antibodies. Cytoplasmic expression of Nm23-H1 and maspin was found in 90 of all investigated cases. In 60 cases maspin protein was found also in nucleus. Medium/high Nm23-H1 cytoplasmic expression level was associated with tubular type of adenocarcinoma with deeper invasion of cancer into intestinal wall (T3, T4) and presence of vascular invasion. Medium/high expression level of maspin was connected uniformly with bad prognostic features: low differentiation of tumors (G3), deeper invasion of cancer (T3, T4) presence of nodular and distant metastases, higher Astler-Coller stage (C1, C2, D) and presence of vascular invasion. No statistically significant associations between presence of nuclear maspin expression and any clinicopatological and biological features were stated. Cytoplasmic medium/high expression level of maspin but no Nm23-H1 and no presence of maspin nuclear expression was found as independent bad prognostic factor in the investigated group of patients. Measurement of level and cellular pattern of maspin expression could be valuable for predicting disease course in patients suffering from colorectal cancer.

Quantitative analysis of the p65 gene expression in patients with coloroctal cancer.

P65 gene expression level was determined in colon cancer cases by means of real-time PCR. 51 cases of colorectal carcinomas showing positive RT-PCR signals for P65 gene expression selected from 109 frozen samples were further investigated by quantitative real-time PCR. P65 levels were higher in cancer with metastases to lymph nodes and distant metastases. Higher levels were observed in more advanced cases classified as III and IV according to pTNM classification. In two groups of patients with vessel invasion and absence of lymphocytes in tumour tissue, the presence of P65 expression correlated with shorter survival time. Quantitative results confirmed that P65 gene expression in colon cancer is engaged in the process of metastasis formation and could be correlated with worse prognosis for the patients.

Expression of the P65 gene in gastric cancer and in tissues with or without Helicobacter pylori infection.

A 65-kDa tumor-associated protein (P65) is a potential non- specific tumor marker expressed by many types of tumor cells. Our recent studies indicate that P65 gene expression is connected with poor prognosis for the patients with colorectal cancer. In the present study P65 gene expression was determined by means of RT-PCR in the group of 22 gastric cancer and adjacent normal gastric mucosa. Its presence was correlated with some parameters of clinical staging. P65 gene expression was also determined in 102 tissue antral gastric endoscopic biopsy specimens from the patients suspected of H. pylori infection. The presence of H. pylori infection was determined by urease test. We found that in the group of gastric cancers, similarly to colorectal cancer, P65 gene expression was connected with poor clinicopathological parameters as T3, lymph nodes and distant metastases. There was no dependence between P65 gene expression and H. pylori infection. However, more often P65 gene expression was detected in the group of infected men than women. There was also a statistically significant dependence between age and P65 gene expression in the group of people above 60 years old. It could be then postulated that P65 gene expression is connected with poor prognosis for the patients suffering from gastric cancer and that this expression does not depend on H. pylori infection.

Cyclin D1 protein and CCND1 gene expression in colorectal cancer.

AIMS: To report the expression of cyclin D1 protein and its gene in a series of colorectal adenocarcinoma. METHODS: One hundred and eleven specimens of colorectal carcinomas and adjacent normal colorectal mucosa were investigated by staining with a monoclonal antibody against cyclin D1 and by RT-PCR. RESULTS: Expression of CCND1 gene was found in 54 out of 111 cases of colorectal cancers, while in normal mucosa the expression of this gene was not observed. Cyclin D1 protein expression was checked in the same group of adenocarcinoma cases. Presence of this protein was observed in 69 cases and for 43 of them also expression of its gene was found. Dependence between the presence of protein and the gene expression was statistically significant (p=0.0002). In the group of cases where CCND1 gene expression was detected, high level of its protein expression was found in 20 cases. The CCND1 gene expression was associated with metastases to lymph nodes (p=0.0181) and also with distant metastasis (p=0.0204). CONCLUSIONS: The combined measurement of both the gene and its protein product, is an important contribution to the study of molecular markers in histological material.

Binding of endomorphin-2 to mu-opioid receptors in experimental mouse mammary adenocarcinoma.

Endomorphin-2 (Tyr-Pro-Phe-Phe-NH2) binds with high affinity and selectivity to the mu-opioid receptor. In the present study, [125I]endomorphin-2 has been used to characterize mu-opioid-binding sites on transplantable mouse mammary adenocarcinoma cells. Cold saturation experiments performed with [125I]endomorphin-2 (1 nM) show biphasic binding curves in Scatchard coordinates. One component represents high affinity and low capacity (K(d) = 18.79 +/- 1.13 nM, B(max) = 635 +/- 24 fmol/mg protein) and the other shows low affinity and higher capacity (K(d) = 7.67 +/- 0.81 microM, B(max) = 157 +/- 13 pmol/mg protein) binding sites. The rank order of agonists competing for the [125I]endomorphin-2 binding site was [d-1-Nal3]morphiceptin > endomorphin-2 >> [d-Phe3]morphiceptin > morphiceptin > [d-1-Nal3]endomorphin-2, indicating binding of these peptides to mu-opioid receptors. The uptake of 131I-labeled peptides administered intraperitoneally to tumor-bearing mice was also investigated. The highest accumulation in the tumor was observed for [d-1-Nal3)morphiceptin, which reached the value of 8.19 +/- 1.14% dose/g tissue.

Expression of p65 gene in experimental colon cancer under the influence of 5-fluorouracil given alone and in combination with hormonal modulation.

The effect of tamoxifen (TAM), lanreotide (LAN) and 5-fluorouracil (5-FU), given separately or together, on p65 gene expression in murine Colon 38 cancer was investigated by RT-PCR method. The findings were compared with cell proliferation determined by bromodeoxyuridine (BrdU) labeling index, apoptosis visualized by TUNEL method and tumor mass. It was found that in the control group (mice bearing colon cancer without treatment) the expression of p65 gene was present in 57% of investigated samples. In the groups treated with TAM or LAN p65 gene expression was detected in 87.5% and 83.3% of analyzed cases, respectively. Both these substances increased apoptotic index in Colon 38 cancer and LAN also decreased the proliferation index. After a combined treatment with TAM and LAN a percentage of p65 positive cases was similar to that of the control group and equaled approximately 60%. This treatment did not increase proapoptotic effects of these drugs, and even reduced the antiproliferogenic effect of LAN. In the group treated with 5-FU and LAN p65 gene expression was also close to the control value (about 66%). Similarly in this group the combined treatment with these two drugs did not cause any favorable effect on proliferation and apoptosis. Moreover, in this group even reduced antiproliferogenic effect of LAN was observed. In the group with 5-FU alone the expression of p65 was present in about 80% of samples. The treatment with 5-FU increased apoptotic index and did not change proliferation. In the group treated with a combination of TAM and 5-FU all analyzed cases showed the presence of p65 gene expression. Previously, we observed in this group the most pronounced and synergistic effect of these substances on the inhibition of cell proliferation and tumor mass reduction. Based on these findings we conclude that p65 gene expression in murine Colon 38 cancer tissues can be modulated via chemotherapy (5-FU) and also via hormonal modulation (TAM and LAN).

Usefulness of polyclonal antibodies raised against P65 oncofetal protein in immunohistochemical diagnosis of ductal breast cancer.

Paraffin-embedded infiltrating ductal breast cancer tissue slides (135) were analyzed by immunohistochemistry with the use of rabbit polyclonal anti-P65 oncofetal protein and mouse monoclonal anti-estrogen/progesterone receptor (ER, PR) antibodies. Analysis with anti-P65 antibody revealed the positive cytoplasmic reaction in 83 cases, 98 showed the nucleic reaction and 3 were immunologically negative. Among the analyzed cases 49 revealed both cytoplasmic and nucleic reactions. For the whole group of cancers the correlation was found between ER or PR level and P65 cytoplasmic reaction (r = 0.77 and 0.66, respectively) and low inverse correlation with nucleic localization of P65 protein. The percentage of positive cells with cytoplasmic expression of P65 was significantly higher in more histologically differentiated cancers (grade I and II according to Bloom and Richardson) than in grade III. Opposite tendency was observed for the nucleic expression of P65 protein. The percentage of immunopositive nuclei grew with the advance of the disease and was the highest in poorly-differentiated (grade III) tumors. The tumors with P65 cytoplasmic reaction were mainly small (T1, T2), without metastases to lymph nodes (N0) and distant metastases (M0). The dependence between P65 protein localization and clinical stage of disease (TNM classification) was evaluated statistically. The straight dependence existed between P65 nucleic reaction and tumor size (p = 0.0002), metastases to lymph nodes (p = 0.0032) and distant metastases (p = 0.0006). The obtained results suggest that the transfer of P65 protein from cytoplasm to nuclei of the breast cancer cells is connected with more clinically advanced stages and worse prognosis for the patients.

HMGI(Y) gene expression as a potential marker of thyroid follicular carcinoma.

BACKGROUND: We assessed HMGI(Y) gene expression in thyroid tumors, control thyroid tissue and in the blood of patients diagnosed with papillary and follicular thyroid cancers to try to differentiate between malignant and benign disease. METHODS: HMGI(Y) gene expression was analyzed by reverse transcriptase-polymerase chain reaction (RT-PCR) in 60 cases of thyroid tumors. Among this number 11 were diagnosed as papillary carcinoma, 37 as follicular carcinoma, and 12 as follicular adenoma. All carcinoma cases selected for this study were classified according to the tumor, lymph node metastases, distant metastases (TNM) classification. RESULTS: HMGI(Y) gene expression was detected only in follicular carcinomas, whereas in papillary carcinomas, follicular adenomas and control tissues there was no positive reaction. In follicular carcinomas the percentage of positive cases (number of samples with presence of HMGI(Y) gene transcript) was the highest and reached approximately 84. There was no statistical dependence between the presence of HMGI(Y) gene expression and tumor size or the presence of lymph node and distant metastases. HMGI(Y) gene expression was also analyzed in whole blood taken from a selected group of patients diagnosed with papillary or follicular carcinomas. Among follicular carcinomas there were 83% of positive cases, whereas among papillary carcinomas there were only 6%. CONCLUSIONS: On the basis of our study, we conclude that HMGI(Y) gene expression analysis could be helpful in differentiation between follicular carcinoma and adenoma.

Uptake of radiolabeled morphiceptin and its analogs by experimental mammary adenocarcinoma: in vitro and in vivo studies.

Morphiceptin (Tyr-Pro-Phe-Pro-NH(2)) and its analogs modified at position 3: [D-Phe(3)]morphiceptin, [D-ClPhe(3)]morphiceptin and [D-Cl(2)Phe(3)]morphiceptin were synthesized and labeled with [(125)I] or [(131)I]. Their binding to membranes isolated from experimental adenocarcinoma was examined in vitro with the use of a cross-linking assay followed by the Western blot technique. The radioactive complex had molecular weight of about 65 kDa and was detectable by anti-mu-opioid receptor polyclonal antibody. Expression of the mu-opioid receptor in mouse mammary adenocarcinoma was confirmed by reverse transcriptase-polymerase chain reaction. The binding studies showed the highest affinity and capacity for [D-Phe(3)]morphiceptin (K(d) 0.39 and B(max) 1112) and [D-ClPhe(3)]morphiceptin (K(d) 1.8 and B(max) 220). Morphiceptin and its D-Cl(2)Phe analog had significantly lower B(max) values (131 and 83, respectively). Biodistribution experiments in tumor-bearing C3H/Bi mice with the use of the (131)I-labeled peptides confirmed the results of our in vitro studies. The highest accumulation of radioactive peptides in the tumor tissue was also found for peptides with D-Phe and D-ClPhe.

Expression of the p65 gene in patients with colorectal cancer: comparison with some histological typing, grading and clinical staging.

AIMS: P65 protein/gene is a potential, non-specific tumour marker expressed by different types of neoplasms. In this study p65 gene expression was estimated in a group of colorectal cancers and compared with some histological features, grading and clinical staging of the neoplasms to assess its role as a prognostic marker for colorectal cancer. METHODS: 109 pairs of frozen samples of colorectal carcinomas and adjacent normal colorectal mucosa and four samples of tissue from patients without neoplastic diseases were analysed by means of RT-PCR. RESULTS: Expression of p65 gene was found in 51 out of 109 cases of colorectal cancers. For 19 of them expression of examined gene was observed both in cancer and corresponding healthy mucosa. p65 Gene expression was associated with more advanced tumours (T3, T4; p=0.0003) with metastases to lymph nodes (N1, N2; p=0.0003) and distant metastases (p=0.0005). We did not find association between the age, gender, tumour localization, histological type and p65 gene expression. CONCLUSIONS: p65 Gene expression in primary tumour tissue is associated with poor prognosis for the patients with colorectal cancer in this series.

HMGI(Y) gene expression in colorectal cancer: comparison with some histological typing, grading, and clinical staging.

We investigated HMGI(Y) gene expression in 81 pairs of frozen samples obtained from colorectal carcinomas and adjacent normal colorectal mucosas and in four samples from colorectal mucosa from patients without neoplastic diseases. In this group, HMGI(Y)-positive/-negative expression was compared with some histological features, grading, and clinical staging of neoplasms investigated to assess its potential role as a prognostic marker for colorectal cancer. Expression of HMGI(Y) gene was found in 51 of 81 cases of colorectal cancers, while, in normal mucosa, expression of this gene was not observed. HMGI(Y) gene expression was associated with more advanced tumors (T3, T4) and metastases to lymph nodes (N1, N2). The most interesting finding was that expression of this gene correlated with distant metastases. HMGI(Y) gene expression was detected in all cases classified as M1 (n = 19, p = 0.0008). We did not find any association between age, gender, tumor localization, histological type and this gene expression.

Synthesis of novel morphiceptin analogues modified in position 3 and their binding to mu-opioid receptors in experimental mammary adenocarcinoma.

Binding of the (125)I-labeled mu-opioid receptor selective ligands, morphiceptin (Tyr-Pro-Phe-Pro-NH(2)) and [D-Phe(3)]morphiceptin, to membranes isolated from experimental mouse mammary adenocarcinoma was examined in vitro using a cross-linking assay followed by a Western blot technique. The radioactive complex had a molecular weight of about 65 kDa and was detectable by anti-mu-opioid receptor antibody, indicating the presence of mu-opioid receptors in tumor membranes. A series of new morphiceptin analogues, modified at the pharmacophoric position 3, was synthesized in order to find the correlation between the lipophilicity, electronic and steric properties of the amino acid in this position and the in vitro affinity of new analogues for mu-opioid receptors on mouse brain and tumor membranes. In in vivo studies the uptake of (131)I-labeled analogues by experimental mammary adenocarcinoma was estimated. The highest affinity for mu-opioid receptors in both, in vitro and in vivo experiments was observed for [D-Phe(3)]morphiceptin and [D-ClPhe(3)]-morphiceptin.

p65 and c-erbB2 genes expression in breast tumors: comparison with some histological typing, grading and clinical staging.

Using PCR technique we have analyzed p65 and c-erbB2 genes expression in 47 frozen tissue slides taken from patients diagnosed as ductal and lobular breast cancer, classified as G3, and in a limited panel of proliferative breast disease cases. Expression of p65 was generally connected with small tumor size and with absence of metastases in regional lymph nodes. We have found interdependence between p65 gene expression and negative states of lymph nodes. On the contrary, c-erbB2 expression was observed in patients with large tumors and with metastases to the regional lymph nodes. Between both genes (p65 and c-erbB2) opposite interdependence was found. No statistical dependence between estrogen/progesterone receptor levels and p65 or c-erbB2 expression were noticed. The presence of p65 expression appeared in the group of proliferating breast disease cases which were connected with higher risk of breast cancer. Lack of p65 expression accompanied cases which were classified as fibroadenoma.

Expression of C-ERBB2 and P65 genes and their protein products in follicular neoplasms of thyroid gland.

C-ERBB2 and P65 gene expression was investigated by reverse transcriptase polymerase chain reaction method (RT-PCR) in thirty follicular thyroid cancers and twenty follicular adenomas. Additionally, the cancers and adenomas were stained by immunohistochemistry for the expression of their protein products. We did not observe P65 gene expression in any of the analyzed follicular cancers (n=30) but it was observed in 13 out of 20 (65%) follicular adenomas. The presence of C-ERBB2 gene expression was found in 18 (90%) follicular adenomas but not in cancers. There were 10 (50%) adenomas and 11 (36.7%) cancers with positive staining for C-ERBB2 protein and 15 (75%) adenomas and 2 (6.7%) cancers with positive staining for P65 protein. We conclude that expression of C-ERBB2 and P65 genes is associated with follicular adenoma but not with cancer of thyroid gland.

Expression of p65, DD3 and c-erbB2 genes in prostate cancer.

The expression of p65, DD3 and c-erbB2 genes was analyzed in 39 histologically verified human prostate cancers. The expression of p65 and DD3 genes was observed in significant percentage in well- and moderately-differentiated tumors. Both genes expression was lower in poorly differentiated tumors. On the contrary, c-erbB2 gene expression increased with advanced histological grading and reached the highest percentage in poorly-differentiated cancers. In the all investigated groups straight dependence between p65 and DD3 genes expression occurred. Opposite dependence was noticed in expression of p65/DD3 and c-erbB2 genes.

Uptake of radiolabelled alpha-fetoprotein by experimental mammary adenocarcinoma and adenoma: in vivo and in vitro studies.

The biodistribution of iodine-labelled alpha-fetoprotein ( I-AFP) in experimental mammary tumours was studied. C3H mice with subcutaneously transplanted mammary adenocarcinoma and Sprague-Dawley rats treated with -methyl- -nitrosourea for mammary adenoma induction were used as animal models. The accumulation of labelled I-AFP in mouse mammary adenocarcinoma was significantly higher than that in rat mammary adenoma. The tumour/muscle radioactivity ratios increased with time and, 48 h after intravenous injection, were estimated as 23.4 and 6.7, respectively. For experiments, extracts from both mammary tumours were prepared. The extracts were subjected to sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE), transferred to polyvinylidene difluoride (PVDF) membranes and incubated with I-AFP. A single major AFP-binding protein with a molecular weight of about 30 kDa was detected in both extracts. The amount of AFP-binding protein was clearly higher for adenocarcinoma than for adenoma. In the presence of cross-linking reagent, I-AFP formed a complex (about 100 kDa) with adenocarcinoma proteins.