Molecular pathology of ovarian carcinomas

 There is evidence that ovarian cancer may be derived from the progressive transformation of benign and/or borderline tumours. Mutations involving different oncogenes and tumour suppressor genes accumulate during the process of malignant transformation, and the alterations of genes involved in the pathogenesis of familial ovarian cancer are probably early events in ovarian tumorigenesis. BRCA-1 and BRCA-2 act as classical tumour suppressor genes in hereditary tumours, but their role in sporadic tumours remains controversial; however, a high frequency of allele losses in BRCA-1 (17q) and BRCA-2 (13q) loci has been observed in both familial and sporadic tumours. The possible role of mismatch repair genes and microsatellite instability is also controversial, but a role for them has been proposed in borderline tumours. Mutations in K-ras are specific for mucinous tumours and may be related to mucinous differentiation. Finally, a role in tumour progression has been proposed for both c-erb B-2 and p53, but their practical value in prognosis remains questionable. Received: 29 May 1997 / Accepted: 2 April 1998     

Genetic aspects of prostate cancer

 Despite its high incidence and mortality rate, the molecular mechanisms underlying the oncogenesis and progression of prostate cancer are still unclear. This review, based on recently published data, surveys the current state of knowledge of human prostate oncogenesis, dealing with genetic predisposition in familial clusters of prostate cancer, providing new information on the somatic genetic alterations, which have been approached in four ways (measurement of DNA content, cytogenetic analysis, in situ hybridization, and molecular analysis), and investigating the problems of androgen independence and intratumour heterogeneity in prostate tumours. Lastly, the potential clinical applications of the genetic alterations, which may become important in the near future, are addressed. Received: 24 October 1997 / Accepted: 16 January 1998     

Developmental noise,ageing and cancer

Development is a very robust but far from perfect process, subjected to random variation due to the combined factors that constitute the so-called developmental noise. The effects of early developmental noise may have long-term consequences resulting from slight differences in the make-up and organisation of the former developing system. Here we present evidence suggesting that cancer is not an acquired but an intrinsic process resulting from random factors acting during early development, thus leading to a mixture of susceptibility types that may develop cancer sooner or later, depending on the combination of the environment acting upon such different susceptibility types. We discuss evidence suggesting that some supposedly tumour-suppressor functions, such as those associated with the p53 protein, actually evolved as buffering functions against the early effects of developmental noise that might compromise the stability of embryonic cells and hence of development. Ageing is a stochastic process characterised by progressive failure of somatic maintenance and repair. We put forth the notion that progressive loss of the morphological coherence of the organism (morphological disorder) is a form of ageing, and that morphological disorder is the common theme of most types of cancer. Thus, we suggest that the exhaustion of both developmental constraints and buffering developmental mechanisms link ageing and cancer. Moreover, we propose that cancer may represent one of the most radical forms of ageing, because it generally satisfies the criteria of senescence: intrinsicality, progressiveness and deleteriousness.     

Sun-exposure- and aging-dependent p53 protein accumulation results in growth advantage for tumour cells in carcinogenesis of nonmelanocytic skin cancer

 Three hundred and sixteen patients with nonmelanocytic skin cancer, including 46 cases of Bowen’s disease (BOD), 134 cases of squamous cell carcinoma (SCC), and 136 cases of basal cell carcinoma (BCC), were examined immunohistochemically using monoclonal antibody DO-7 to assess p53 protein accumulation related to sun exposure and ageing, and growth and differentiation of skin cancer and its precursors. The rates of p53 immunostaining of BOD, SCC and BCC were 80.4%, 76.1% and 70.6%, respectively. p53-positive cells were present not only in cancer nests, but also in dysplastic and even morphologically normal epidermis adjoining cancers. Sun exposure was statistically correlated with the p53 immunostaining scores in morphologically normal epidermis of the three skin cancers and in cancer nests of SCC and BCC. The positivity and score of p53 protein often differed significantly among the three types of cancer, especially in regions of dysplasia. Interestingly, differentiation of SCC was correlated with individual p53 scores for dysplasia and cancer nests, especially for dysplasia. BOD, as the precursor of SCC, demonstrated the strongest p53 expression. Furthermore, 12.3% cases with p53 negative cancer nests showed p53-positive reaction in dysplasia and in morphologically normal epidermis. It seems that the accumulation of p53 protein plays a part in precancerous lesions and in the genesis of more highly differentiated types of skin cancer and affects mainly the growth of tumour cells rather than their differentiation. For BCC, however, age was significantly related to p53 expression. Our findings suggest that overexpression of p53 in normal skin and cancer nests of SCC and BCC is significantly related to sun exposure, that the expression of p53 in BCC is an age-dependent process, and that the early accumulation of p53 protein may be a useful predictor for the detection of nonmelanocytic skin cancer. Received: 7 July 1998 / Accepted: 5 November 1998     

Relaxin promotes differentiation of human breast cancer cells MCF-7 transplanted into nude mice

Previous studies showed that the hormone relaxin acts on human breast cancer MCF-7 cells in vitro by modulating cell proliferation and promoting cell differentiation toward a duct epithelial phenotype. The present study was designed to investigate whether relaxin retains these properties when acting in vivo on MCF-7 cell tumors developed in athymic nude mice. Mice bearing MCF-7 cell tumors transplanted under the mammary fat pad and estrogenized to sustain tumor growth were treated systemically with relaxin (10 μg/day) for 19 days. Vehicle-treated mice were used as controls. Thirty days later, the mice were sacrificed and tumor fragments were analyzed by light and electron microscopy and immunocytochemistry. Measurements of tumor volume were recorded weekly for the overall experimental period. The results obtained indicate that relaxin treatment promotes differentiation of tumor cells towards both myoepithelial-like and epithelial-like cells, as judged by the ultrastructural features of the cells and by the increased expression of smooth muscle actin and cadherins. Measurements of tumor size and of the number of cycling cells show that relaxin, at the doses and times of exposure used in this study, does not significantly influence tumor growth and cell proliferation. Received: 3 March 1999 / Accepted: 28 May 1999     

Histopathology of tumour associated sarcoid-like stromal reaction in breast cancer

Summary In 5 cases of invasive ductal and lobular carcinoma of the breast multiple epithelioid and giant cell containing granulomas were detected, localized mainly in circumferential regions, but also in the center of the carcinomas. These granulomas were interpreted as sarcoid-like stromal reactions, occurring as sarcoid-like lesions in uni- and bilateral primaries, in a recurrent tumour, and also in axillary lymph nodes. Histopathologically, these granulomas were not quite uniform, some of them corresponding to typical sarcoidosis, others showing marked proliferations of epithelioid or giant cells or containing fibrinoid exudate or necroses. The granulomas were surrounded by dense infiltrates of mononuclear cells. Tuberculosis and mycosis was excluded. There were no hints of generalized sarcoidosis. Pathogenetically, these are reactions in the tumour stroma of varying intensity, and are not caused by necroses of the tumour tissue nor by microbial infections. Such tumour-associated sarcoid-like stroma reactions are interpreted as a T-cell mediated immune response to an antigen expression of the carcinoma acting as the local trigger; in 2 cases they were connected with sarcoid-like lesions of the axillary lymph nodes. Their occurrence in bilateral carcinoma of the breast points to an immunological disposition for this special kind of host-versus-tumour response. The intensity of these changes in a recurrent tumour reflects an immunological hypersensitivity reaction.The pathogenetic and differential diagnostic aspects of epithelioid granulomas of the female breast in chronic granulomatous mastitis, panniculitis, foreign body reaction, rare infections, and in therapeutically induced sarcoidosis are described and discussed.Dedicated to Prof. Dr. K. Lennert, Kiel, in Honour of his 65th Birthday     

Adenomyoepithelioma of the breast with malignant features

 The clinico-pathological features of 7 cases of adenomyoepithelioma of the breast with features suggestive of malignancy are presented. There was a high incidence of local tumour recurrence, in 2 cases as high-grade infiltrating carcinoma of the breast of no special type (”ductal”, grade III). One patient died as the result of a clinically diagnosed cerebral metastasis. Histological examination of the primary breast tumours reveals two main patterns: (1) tumours consisting in part of typical adenomyoepitheliomas but which merge with areas of obviously invasive malignant cells and (2) neoplasms that have the overall architecture of an adenomyoepithelioma but which, on close examination, are found to contain foci of cellular atypia and increased mitotic activity. The two patterns of tumour exhibit the same clinical behaviour and should be distinguished from adenomyoepitheliomas, which are cytologically bland throughout. Received: 3 April 1997 / Accepted: 27 May 1997     

Alterations of basement membrane in di-isopropanolnitrosamine- induced carcinogenesis of the rat thyroid gland: an immunohistochemical study

Alterations of basement membrane (BM) in di-isopropanolnitrosamine (DIPN)-induced carcinogenesis of the rat thyroid gland were examined by means of immunohistochemical localization of collagen type IV (CN-IV), laminin (LN), and fibronectin (FN) in pre-nodular and nodular thyroid lesions, correlating with the morphogenesis and proliferative activity of these lesions. Adult male rats of the Wistar strain were injected s.c. in the back with DIPN, and the thyroid glands were removed at the 15th and 30th week of treatment. Each of 133 thyroid lesions was histochemically analyzed. The follicular epithelial BM as revealed by CN-IV and LN was discontinued or completely lost during the progression of thyroid lesions from pre-nodular to nodular lesions and finally overt carcinomas. At the same time, the BM of vascular endothelial cells demonstrated a loss of dense capillary networks of follicles, a sinusoidal dilatation and, predominantly in carcinomas, development of interstitial-type blood vessels. However, FN, which was hardly stained in the normal thyroid tissue, was remarkably deposited in the interstitium of invasive carcinomas. These observations strongly suggested that alterations of BM structure play a key role in the morphogenesis of rat thyroid tumors, and that the expression of FN is an important step in the invasive growth of thyroid tumors. Received: 12 October 1999 / Accepted: 30 December 1999     

Frequency of apoptosis relates inversely to invasiveness and metastatic activity in human colorectal cancer

 The frequency of apoptosis was determined in 102 cases of human colorectal cancer. The results were correlated with the frequency of cell proliferation and with clinicopathological characteristics such as degree of differentiation, invasiveness and metastasis. As a marker of apoptosis, intranuclear DNA strand breaks were localized with in situ nick translation (ISNT). As a marker of proliferation, proliferating cell nuclear antigen (PCNA) was localized immunohistochemically. The numbers of nuclei positive with ISNT and for PCNA per 1,000 nuclei on tissue sections were obtained. The labelling indices were compared with clinicopathological characteristics for each tumour. The ISNT labelling index of well differentiated colon carcinomas was higher than that of poorly differentiated carcinomas. Among similarly differetiated cancers, ISNT L.I. of colon carcinomas classified as Dukes A was higher than Dukes B/C, and L.I. of carcinomas which did not metastasize to lymph node or liver was higher than that of carcinomas which metastasized. The PCNA labelling index did not correlate with any of the clinicopathological characteristics or with the ISNT labelling index. The data suggest that apoptosis indices severe as a marker of tumour progression. Received: 28 October 1996 / Accepted: 15 April 1997     

Chromosome 3p and breast cancer

 Solid tumors in humans are now believed to develop through a multistep process that activates oncogenes and inactivates tumor suppressor genes. Loss of heterozygosity at chromosomes 3p25, 3p22–24, 3p21.3, 3p21.2–21.3, 3p14.2, 3p14.3, and 3p12 has been reported in breast cancers. Retinoid acid receptor β2 (3p24), thyroid hormone receptor β1 (3p24.3), Ras association domain family 1A (3p21.3), and the fragile histidine triad gene (3p14.2) have been considered as tumor suppressor genes (TSGs) for breast cancers. Epigenetic change may play an important role for the inactivation of these TSGs. Screens for promoter hypermethylation may be able to identify other TSGs in chromosome 3p. Alternatively, use of an “epigenetic modifier” may enhance the response to another type of agent for breast cancer. Received: April 30, 2002 / Accepted: May 27, 2002     

Immunohistochemical expression of cathepsin D in correlation with extracellular matrix component, steroid receptor status and proliferative indices in breast cancer

 In 87 breast cancer patients, the immunohistochemical expression of the basement membrane (BM)-degrading enzyme cathepsin D (CD) was correlated with the expression of extracellular matrix components, with growth fraction, steroid receptor content and with the other conventional prognostic variables in breast cancer. Only 6.25% of tumours had laminin-defined BM, while 86.8% showed staining for fibronectin. CD was also identified in carcinoma cells (cancer cell CD; CCCD) and in stromal cells (stromal cell CD; SCCD). Forty-five percent of tumours showed CCCD and 47.5%, SCCD expression. CCCD expression was significantly correlated with positive oestrogen receptor content, with low Ki-67 and high PCNA score and with SCCD expression. There was no correlation with collagen type IV, laminin or fibronectin. SCCD expression was positively correlated with collagen type IV, laminin expression and tumour grade. The data suggest that the CD of tumour cells and the CD of tumour-associated macrophages have different roles in breast cancer. CCCD correlates with cell proliferation and is regulated by oestrogens, while SCCD relates to cell differentiation, is oestrogen-independent, and has a proteolytic role in the breakdown of BM components. Received: 30 September 1996 / Accepted: 7 April 1997     

Biological and prognostic significance of stratified epithelial cytokeratins in infiltrating ductal breast carcinomas

 The biological significance of the differential expression of cytokeratin (CK) polypeptides in breast carcinomas is unclear. We examined the CK profiles of 101 primary infiltrating ductal breast carcinomas using monoclonal antibodies directed against 11 different CKs and against vimentin. Two major CK phenotypes were distinguished: first, a phenotype expressing only the simple-epithelial CKs 7 (variably), 8, 18 and 19, and secondly, a bimodal phenotype co-expressing significant amounts of one or more of the stratified-epithelial CKs 4, 14 and 17. The vast majority of G1 and G2 carcinomas had the simple-epithelium phenotype, as did a subgroup of G3 carcinomas. Interestingly, the majority (62%) of G3 carcinomas exhibited the bimodal phenotype, with the expression of CKs 4, 14 and 17 being statistically correlated with poor histological differentiation and absence of steroid hormone receptors. The distribution of vimentin only partially overlapped with that of these stratified-epithelial CKs. Prognostic analyses suggested that the presence of CKs 4, 14 and/or 17 was associated with short overall and disease-free survival in subgroups comprising G3, oestrogen-receptor-negative and vimentin-negative tumours. In node-positive tumours the correlation between these CKs and a shorter disease-free interval attained statistical significance (log rank, 0.0096). Thus, abnormal CK profiles in ductal breast carcinomas appear to reflect disturbed regulation of differentiation-related gene expression programmes and may prove to be of clinical value. Received: 26 August 1997 / Accepted: 11 February 1998     

Hormones and breast cancer

The incidence of breast cancer in women varies with age, mammarygland mass and exposure to endogenous and exogenous hormones.Age is the single most important factor and if, as projected,32% of women will be aged >60 years by 2050, world breast cancerincidence will exceed the current 10⁶ per year. Hormonal influencesthat affect growth of the mammary gland increase the risk ofbreast cancer; for example earlier menarche and later menopause.Childbearing protects against later development of breast cancer,and breastfeeding further decreases the risk. The breast cancerrisk declines more with increasing total duration of breastfeeding.Exposure to hormonal contraceptives has been evaluated in acombined reanalysis of data from 51 epidemiological studies.There is a small transient increase in the relative risk ofbreast cancer among users of oral contraceptives but, sinceuse typically occurs at young ages when breast cancer is relativelyrare, such an increase would have little effect on overall incidencerates. In contrast, exposure to menopause hormone treatmentoccurs when the baseline risk of breast cancer is higher, andepidemiological studies and randomized controlled trials consistentlyfind an increase in breast cancer risk with exposure to combinedestrogen and progestogen. Women with a family history of breastcancer in first degree relatives have an increased risk of breastcancer but there is no evidence to suggest that this differsaccording to a woman's use of oral contraceptives or menopausehormone treatment. Selective estrogen receptor modulators areuseful in the treatment and/or prevention of breast cancer dependingon the specific agonist or antagonist effects on estrogen targettissues.     

Genetics of cancer predisposition and progression

Summary The development of human cancer is a multistep process that entails a progressively more malignant phenotype through the evolution of cellular subsets with increasing numbers of genetic alterations. Here we review the molecular genetics of human cancer predisposition and progression and describe paradigmatic cancer types and cancer syndromes. We also briefly consider the future impact of molecular biology on cancer diagnosis and treatment.Abbreviations APC adenomatous polyposis coli - BWS Beckwith-Wiedemann syndrome - DCC deletion in colorectal cancer - EGFR epidermal growth factor receptor - FAP familial adenomatous polyposis - IGF insulin-like growth factor - LOH loss of heterozygosity - MEN multiple endocrine neoplasia - NF neurofibromatosis - NSCLC non-small-cell lung cancer - RCC renal-cell carcinoma - SCLC small-cell lung cancer - VHL von Hippel-Lindau syndrome - WAGR Wilms' tumor, aniridia, genitourinary anomalies, mental retardation syndrome - WT Wilms' tumor - ZF zinc finger     

Field cancerization in mammary carcinogenesis — Implications for prevention and treatment of breast cancer

The natural history of breast cancer unfolds with the development of ductal carcinoma in situ (DCIS) in normal breast tissue, and evolution of this pre-invasive neoplasm into invasive cancer. The mechanisms that drive these processes are poorly understood, but evidence from the literature suggests that mammary carcinogenesis may occur through the process of field cancerization. Clinical observations are consistent with the idea that (i) DCIS may arise in a field of altered breast epithelium, (ii) narrow surgical margins do not remove the entire altered field (contributing to recurrence and/or disease progression), and (iii) whole-breast radiation therapy is effective in elimination of the residual field of altered cells adjacent to the resected DCIS. Molecular studies suggest that the field of altered breast epithelial cells may carry cancer-promoting genetic mutations (or other molecular alterations) or cancer promoting epimutations (oncogenic alterations in the epigenome). In fact, most breast cancers develop through a succession of molecular events involving both genetic mutations and epimutations. Hence, in hereditary forms of breast cancer, the altered field reflects the entire breast tissue which is composed of cells with a predisposing molecular lesion (such as a BRCA1 mutation). In the example of a BRCA1-mutant patient, it is evident that local resection of a DCIS lesion or localized but invasive cancer will not result in elimination of the altered field. In sporadic breast cancer patients, the mechanistic basis for the altered field may not be so easily recognized. Nonetheless, identification of the nature of field cancerization in a given patient may guide clinical intervention. Thus, patients with DCIS that develops in response to an epigenetic lesion (such as a hypermethylation defect affecting the expression of tumor suppressor genes) might be treated with epigenetic therapy to normalize the altered field and reduce the risk of secondary occurrence of DCIS or progression to invasive cancer.     

Scar and non-scar ductal cancer of the female breast

Summary Ductal cancers of human female breasts were classified as scar or non-scar type. Of 274 cancers, 144 were scar and 130 non-scar type. Estrogen and progesterone receptors were determined in 191 cases; the cancer was classified as hormone receptor positive if either the estrogen or progesterone receptor level, or both, was over 10 fmol/mg of cytosol protein. The mean age of patients with scar cancer was higher than that of patients with non-scar cancer (59.8 ± 13.5 and 49.4±12.0 years, respectively,p<0.001). A higher number of hormone receptor positive cases was found among the scar than among the non-scar cancers (68 of 94 and 48 of 97 cases, respectively,p<0.01). Within the two groups, the patient's age was not associated with hormone receptor status. Our results indicate that the generally observed tendency for postmenopausal breast cancer to be more often hormone receptor positive than premenopausal cancer may be associated with the histological type and not with the patient's age. Scar cancers were also smaller than 2 cm more frequently than non-scar cancers (p<0.001) and as a group, ductal cancers were smaller in postmenopausal patients than in premenopausal patients (p=0.088). Again, this tendency seemed to be linked with the type of cancer rather than with the patient's age.     

Alterations in tumour suppressor gene p53 correlate with inhibition of thrombospondin-1 gene expression in colon cancer cells

 If activation of the p53 gene is involved in the progression or metastasis of colon cancer, it may affect the angiogenic phenotype in vivo. To verify this hypothesis, we studied the correlation between p53 accumulation and expression of thrombospondin-1 (TSP1) in colon cancer specimens. Levels of TSP1 gene expression were estimated by Northern blotting in 65 colon cancers. Accumulation of p53 and the distribution of TSP1 protein were evaluated immunohistochemically. Various levels of TSP1 gene expression were seen in colon cancers, while p53 accumulation was confirmed in 42 of the 65 colon cancers. The level of TSP1 gene expression demonstrated a significant inverse correlation with p53 accumulation in colon cancer. Colon cancer cells expressed TSP1 protein and p53 accumulation reciprocally in the same nests. These results suggest that alterations in the tumour suppressor gene p53 may inhibit TSP1 expression in colon cancer. Received: 9 April 1998 / Accepted: 19 June 1998     

Expression of cyclin Ds in relation to p53 status in human breast carcinomas

 Cyclin D1 has been reported to be overexpressed in many tumours, including breast carcinomas. Cyclin D1 was first identified as a protooncogene (BCL1/PRAD1), and its overexpression was related to tumour proliferation. The product has also recently been identified as important in mediating cell cycle growth arrest via the p53 pathway in murin fibroblast cell lines. Ninety breast carcinomas previously analysed for p53 status were analysed for amplification of cyclin D1, D2 and D3 genes by Southern blot analysis and for protein expression by immunhistochemistry. In 10 samples gene amplification was detected at the cyclin D1 locus. No gene amplification was detected at the cyclin D2 and D3 loci. Immunoreactivity for cyclin D1 was detected in 38 (42.2%) tumour tissue samples. Fifty samples were immunostained for cyclin D2 and D3. Only 2 samples (4%) showed immunoreactivty for cyclin D2, and 9 samples (18%) for cyclin D3. Cyclin D1 protein overexpression was significantly more often found in tumours with wild type p53 and in tumours with higher grades of differentiation expressing ER. No association was seen between gene amplification of the cyclin D1 gene and p53 status. We conclude there is a relationship between wild type p53 and cyclin D1 protein overexpression in clinical material, indicating that cyclin D1 may be another downstream effector of p53. Received: 25 November 1997 / Accepted: 30 March 1998     

The influence of p53 and associated factors on the outcome of patients with oral squamous cell carcinoma

 In several tumour entities the immunohistochemical detection of p53 has proved to be a predictive factor for the survival of the patients. In this study the effector waf1 and the regulator mdm2 responsible for the inactivation of p53 were also determined in 156 tissue samples of primary squamous cell carcinomas in the oral cavity and oropharynx, their lymph node metastases, and the epithelium outside the invasively growing tumour from 107 patients. In this latter epithelium there was a significant correlation between grade of dysplasia and staining for p53 (P<0.01). In the dysplastic epithelium a significant correlation between p53, waf1, and mdm2 was shown (P<0.05). Differences in the immunohistochemical staining between different blocks of the tumour tissue and also between primary tumours and their lymph node metastases were revealed in 11–44% of cases, but there was no correlation with other variables, such as formation of lymph node metastases. In contrast to the conventional tumour grading and staging, no influence of any of the variables determined on survival or recurrence-free survival could be detected. It seems that p53 and associated factors are important in the early stages of cancerogenesis but not in further tumour progression and metastatic spread. Received: 26 March 1998 / Accepted: 10 June 1998