Characteristics of human tumour xenografts transplanted under the renal capsule of immunocompetent mice.

Human tumour lines established in athymic nude mice were grafted under the renal capsule of immunocompetent mice. Grafts from 27 human tumour lines comprising 9 malignant melanomas, 10 sarcomas, 2 colon carcinomas, 4 lung carcinomas and 2 mammary carcinomas, grew well under the renal capsule of the immunocompetent mice and retained morphological and functional characteristics of the parent tumours, as judged by light and electron microscopy and immunohistochemical examinations. Numerous mitoses were detected. Granulation tissue and necrosis were not predominant features. After Day 4, the grafts became infiltrated from the periphery by mouse inflammatory cells. The infiltration could be prevented by pretreatment of the animals with cyclophosphamide. Anti-human antibodies were detected after Day 3. Single cell suspensions from the subrenal grafts were able to form colonies in soft agar. and upon reimplantation in nude mice, subcutaneous tumours were formed showing that the grafted tumour tissue had also retained its malignant character. Altogether the results support the view that human tumour xenografts grow well under the renal capsule of immunocompetent mice and that the grafts retain important characteristics of the original tumour

Expression of S100A4, E-cadherin, α- and β-catenin in breast cancer biopsies

In 66 breast cancer biopsies, the expression of the Ca2+-binding protein S100A4, E-cadherin, α- and β-catenin was examined by immunohistochemistry, and the results were related to clinical and pathological parameters. High levels of S100A4 were found to significantly correlate with histological grade (P=0.030) and loss of oestrogen receptor (P=0.046), but not to the time interval between surgery and development of distant metastasis (P=0.51) or to patient survival (P=0.89). Loss of E-cadherin expression, associated with altered cell–cell adhesion, showed a highly significant association to overall survival (P=0.020) and metastasis-free period (P=0.0052). In multivariate analysis, only lymph node involvement was a more significant predictor of patient demise. No association was found between expression of S100A4 and any single member of the cadherin–catenin complex, but a trend (P=0.053) towards reduced expression of one or several of these proteins and S100A4 immunoreactivity was observed. In conclusion, although our results suggest an association between S100A4 expression and an aggressive tumour phenotype, no relationship to overall survival was found. Deregulation of E-cadherin expression, however, was of high prognostic significance

Apoptosis and necrosis induced with light and 5-aminolaevulinic acid-derived protoporphyrin IX.

The mode of cell death induced by photodynamic treatment (PDT) was studied in two cell lines cultured in monolayer, V79 Chinese hamster fibroblasts and WiDr human colon adenocarcinoma cells. The cells were incubated with 5-aminolaevulinic acid (5-ALA) as a precursor for the endogenously synthesised protoporphyrin IX, which was activated by light. Free DNA ends, owing to internucleosomal DNA cleavage in apoptotic cells, were stained specifically with a fluorescent dye in the terminal deoxynucleotidyl transferase (TdT) assay. The free DNA ends were measured by flow cytometry and the fractions of apoptotic cells determined. Total cell death was measured in a cell survival assay to determine the necrotic fraction after subtraction of the apoptotic fraction. V79 cells did undergo apoptosis while WiDr cells were killed only through necrosis. With time, the apoptotic fraction of V79 cells increased until a maximum was reached about 3-4 h after ALA-PDT treatment. For increasing ALA-PDT doses, a maximal apoptotic fraction 75-85% of the cells was measured at about 85% of total cell death. The flow cytometric assay of apoptosis was confirmed by the typical ladder of oligonucleosomal DNA fragments obtained from agarose gel electrophoresis, by fluorescence micrographs visualising the induced free DNA ends and by electron micrographs showing the typical morphology of apoptotic cells

Diploid nature of hepatocellular tumours developing from transplanted preneoplastic liver cells.

Hepatocyte suspensions were transplanted to the livers of syngeneic Wistar Kyoto rats by means of intraportal injection. Labelling of the donor cells with 51Cr or tritiated thymidine showed that 20% of the cells survived the transplantation procedure and were permanently retained by the recipient liver. Hepatocytes transplanted from normal livers produced no tumours, whereas donor cells from preneoplastic livers of rats treated with the carcinogens diethylnitrosamine and 2-acetylaminofluorene produced neoplastic nodules and hepatocellular carcinomas in the recipients. The number of tumours per host liver was proportional to the number of hepatocytes transplanted. Treatment of the host rats with phenobarbitone accelerated tumour development, causing liver cancer in the majority of the animals within three months. As opposed to the polyploid surrounding liver, both phenobarbitone-promoted and unpromoted host tumours contained predominantly (70-90%) diploid cells, regardless of the wide range of transplant ploidies (10-80% diploid cells) achieved by means of centrifugal elutriation. The results indicate that all host tumours arise from diploid donor hepatocytes and that the acquisition of a constitutive, predominantly non-polyploidising growth pattern may be a characteristic property of hepatocellular tumours

Prostatic carcinoma: a multivariate analysis of prognostic factors.

Tissue specimens from 150 patients with localised prostatic carcinomas and 116 patients with prostatic carcinomas with distant metastases were analysed for histological grade (WHO and Gleason) and immunoreactivity for prostate acid phosphatase (PAP), prostate-specific antigen (PSA), neurone-specific enolase (NSE), p53 protein, c-erbB-2 protein, cytokeratins (AE1/AE3) and vimentin. After stratification for the presence or absence of distant metastases, multivariate regression analysis revealed that WHO grading was the most powerful independent prognosticator, followed by age and prostate acid phosphatase expression. There was a trend towards reduced survival with decreasing prostate-specific antigen reactivity. The Gleason system showed poor prognostic ability. The analysis predicted reduced survival in the presence of extensive neurone-specific enolase reactivity, mostly because of one case of small-cell carcinoma

Colony forming ability of human breast carcinomas: lack of prognostic significance.

To study whether colony growth in vitro reflects the prognosis of breast cancer patients, specimens from a total number of 138 patients with primary breast carcinomas were cultivated in the Courtenay-Mills soft agar method. The plating efficiency (PE) values were related to various clinical and histopathological parameters. No significant correlation was found between colony forming ability and menopausal status, histopathology, TNM-status or steroid hormone receptor status. The crude survival of the patients was not significantly correlated to the in vitro growth of the tumours; neither was there any difference in relapse-free survival between patients whose tumours failed to grow in vitro and those having growing tumours (PE greater than 0). A multivariate survival analysis of 115 patients with primary tumours without distant metastases revealed that the PE was not a significant independent prognostic indicator, as it gave no additional prognostic information above that of node and ER status. It is concluded that routine measurement of colony formation in vitro is not warranted in the management of breast cancer

DNA ploidy in primary testicular cancer.

The DNA stemline ploidy was measured by flow cytometry (FCM) in 129 samples from paraffin-embedded primary testicular tumours (61 seminomas, 68 non-seminomas). Only one DNA stemline was found in 38 seminomas and 44 non-seminomas. Two seminomas and one non-seminoma were DNA diploid, the other tumours being non-diploid. Twenty-three seminomas and 24 non-seminomas displayed two or three DNA stemlines. The median minimal DNA index (DI) of all seminomas was significantly higher than that of all non-seminomas (1.58 vs 1.43; P: 0.008). Three seminomas removed from two monozygotic twins within 1 week had DIs of 1.66, 1.56 and 1.59. In this limited series there was no association between DNA ploidy of the primary tumour and the metastatic status for either seminomas or non-seminomas. The results support the pathogenetic model stating that at least some (if not all) non-seminomas develop from a seminoma by additional chromosomal aberration. The clinical relevance of DNA stemline ploidy has to be further evaluated in larger series

TP53 allele loss, mutations and expression in malignant melanoma.

p53 alterations at the DNA, mRNA and protein levels were studied in tumour metastases sampled from 30 patients with malignant melanoma. Paraffin-embedded sections from these and an additional 12 patients were examined for the presence of p53 protein. TP53 gene aberrations were found in 7 of 30 (23%) of the patients, six of which showed loss of heterozygosity (LOH). Point mutations were detected in only two cases, one of which had LOH whereas the other was non-informative. Increased levels of p53 mRNA were present in only one tumour with, but in six cases without, detectable DNA abnormalities. Four of the latter and six tumours with normal transcript levels had immunohistochemically detectable levels of p53 protein. In 25 cases in which corresponding primary and metastatic lesions could be compared, closely similar immunoreactivity patterns were observed. Increased expression of the MDM2 gene was found in only one tumour in parallel with overexpression of p53. Altogether, the data indicate that inactivation of the p53 regulatory pathway is not of major significance in the tumorigenesis of malignant melanoma. However, a significant association was found between p53 immunoreactivity and the relapse-free period in patients with superficial spreading melanoma. That increased protein expression was predominantly found in tumours without DNA alterations might suggest a role for the wild-type p53 protein in restricting malignant cell proliferation in these cases

TP53 gene mutations and protein accumulation in primary vaginal carcinomas.

Primary carcinomas from 46 patients were screened for TP53 alterations. Immunohistochemistry demonstrated nuclear TP53 protein accumulation in 22 (48%) cases using the polyclonal CM1 antiserum, whereas 15 (33%) cases showed positive nuclear staining with the mononuclear antibody PAb 1801. Constant denaturant gel electrophoresis (CDGE) was used to screen 27 of the vaginal carcinomas for mutations in the conserved regions of the TP53 gene (exons 5-8). Six of these tumours (22%) contained mutations: four were found in exon 5 and two in exon 8. A total of 50% of the primary vaginal carcinomas carried a TP53 alteration. These results indicate that TP53 abnormalities may be involved in the development of these tumours. However, there was no significant association between TP53 abnormalities and survival

Cultivation of human breast carcinoma in soft agar. Experience with 237 fresh tumour specimens.

A total of 237 breast carcinomas have been studied with the Courtenay-Mills (C-M) soft agar method. Cell yields and plating efficiencies (PE) were recorded after various enzyme treatments. The highest cell yields and PEs were obtained with the combination of collagenase 0.5%, hyaluronidase 1000 IE ml-1 and DNase 0.1% and an incubation time of 2 h. Eighty percent of the specimens gave greater than 10 colonies, and 60% formed greater than 30 colonies permitting chemosensitivity studies. The C-M method gave significantly higher PEs than the Hamburger-Salmon (H-S) method. Hormone supplements (insulin, oestradiol, progesterone, hydrocortisone) and also reduced agar concentrations (less than 0.3%) gave marginal stimulation of colony formation. In chemosensitivity studies involving doxorubicin, vincristine and 4-OOH-cyclophosphamide, the C-M method gave dose-response relationships without plateaus