Surface topography and ultrastructural changes of mucinous carcinoma breast cells.

Mucinous carcinoma of the breast (MCB) is histologically classified into 2 groups: (1) pure MCB and (2) mixed MCB. Pure MCB carries a better diagnosis than mixed MCB. This research relates to the cell surface topography and ultrastructure of the cells in the above cases and aims to find the differences between them, by means of two methods: scanning electron microscopy (SEM) and transmission electron microscopy (TEM). For the SEM examination, it was necessary to initially culture the MCB tissues and then proceed with the usual SEM method. In contrast, for the TEM technique, MCB tissues were initially fixed followed by the classic TEM method. The authors found the topography of pure MCB cases to be without nodes. The cell membrane was smooth, with numerous pores and small ruffles that covered the entire cell. The ultrastructural appearance of the same cases was with a normal cell membrane containing abundant collagen fibers. They also had many small vesicles containing mucin as well as secretory droplets. In contrast the mixed MCB had a number of lymph nodes and their cell surface topography showed stronger changes such as microvilli, numerous blebs, ruffles and many long projections. Their ultrastructure showed very long microvilli with large cytoplasmic inclusions and extracellular mucin collections, electron-dense material vacuoles, and many important cytoplasmic organelles. An important fact is that mixed MCB also contains areas of infiltrating ductal carcinoma. These cells of the cytoplasmic organelles are clearly responsible for the synthesis, storage, and secretion of the characteristic mucin of this tumor type. Evidently, this abnormal mucin production and the abundance of secretory granules along with the long projections observed in the topographical structure might be responsible for transferring tumor cells to neighboring organs, thus being responsible for metastatic disease.

The enigmatic nature of apocrine breast lesions.

Epithelial cells of fetal breast glandular structures, at the third trimester of pregnancy (28 weeks), produce GCDFP-15, in the absence of specific apocrine morphology. Apocrine epithelium of the breast may be a normal process of differentiation rather than a result of metaplasia, and it has been demonstrated that it is estrogen-receptor, progesterone-receptor and bcl-2 negative, but androgen-receptor (AR) positive. The significance of AR expression in apocrine epithelium is uncertain. Apocrine epithelium is seen in a wide spectrum of breast entities, ranging from benign lesions to invasive carcinoma. Breast cancer accounts 32% of all cancer cases among women and is the most common type of cancer in women. Little is known about breast carcinogenesis. Widely, it is accepted that breast cancer, like most other type of cancer, is being developed through the accumulation of genetic aberrations. Apocrine epithelium may reflect instability of the breast epithelium, creating an environment favouring further oncogenic alterations. In the last decade, several lines of evidence support the idea that some breast benign epithelial apocrine lesions are clonal lesions and may be considered as truly pre-malignant or precursors of breast carcinoma. Apocrine changes in many cases do not present any diagnostic difficulty; on the other hand, apocrine proliferations with cytologic atypia can be particularly difficult and challenging. The purpose of this study is to collect and highlight the areas of consensus in the literature as well as the controversial areas concerning the apocrine epithelium of the breast.

DCIS histopathology from a historical perspective.

Ductal carcinoma in situ (DCIS) represents a biologically and morphologically heterogeneous disease. It is characterized by a proliferation of presumably epithelial malignant cells confined within the lumens of the mammary ducts, without evidence of invasion beyond the basement membrane into the adjacent breast stroma. With the widespread use of screening mammography, a dramatic change has occurred in the frequency, management and types of DCIS detected. Historically, there has been some confusion regarding the definition of DCIS and the terminology associated with the histological types of DCIS. In this review, DCIS histopathology from a historical point of view is presented.

Dermatofibrosarcoma protuberans occuring in a child.

Dermatofibrosarcoma protuberans (DFSP) usually occurs in adults, however it can also occur in infancy and childhood. Diagnosis of DFSP in children is quite difficult given the rarity of the tumor and its variegated appearance. The behavior of this neoplasm is of borderline or intermediate malignancy with a high rate of recurrence but limited metastatic potential. We present the case of an eleven-year old boy who presented with a slightly raised, not tender lesion on his right shoulder. It had appeared two years before as a red-brown plaque and since then it had gradually grown to a nodule. An excisional biopsy was performed, and the diagnosis of DFSP was made based on the histological and immunohistochemical findings.

Cell cycle proteins in laryngeal cancer: role in proliferation and prognosis.

A study of laryngeal carcinomas was performed in order to analyze (a) the expression of p53/p21, cyclin D1/cyclin E, p21/p27 (b) the relation of normal and abnormal protein expression, with the proliferation status, as determined by the expression of Ki67 and PCNA and (c) the correlation of our findings with prognosis. We performed a retrospective analysis of 57 cases of squamous cell carcinomas of the larynx. We applied monoclonal antibodies against p53, p21, p27, cyclin D1, cyclin E, Ki67 and PCNA, using streptavidin-biotin method. Analysis of the p53/p21 proteins, revealed abnormalities in 25/37 cases (67.57%), while 12/37 (32.43%) cases displayed normal phenotype (p53-/p21-). Analysis of cyclins revealed overexpression in 17/48 cases (35.42), while the majority 31/48(64.58%) displayed normal phenotype (cyclin D1-/cyclin E-). Concerning CDKIs expression, the majority 30/50(60%) presented high levels of both inhibitors (p21+/p27+). Cases with simultaneous overexpression of CDKIs demonstrated significantly higher levels of Ki67 protein (p = 0.05). Analysis of p53/p21, cyclin D/cyclin E, p21/p27 patterns showed no association between the presence of one or two alterations and prognosis. In conclusion, we demonstrated that p53 tumor suppressor pathway is frequently disrupted in laryngeal cancer. Furthermore, levels of CDKIs, although they act as cell cycle activity blockers, are not reliable markers for the estimation of laryngeal neoplastic cells growth fraction.

The role of fine-needle aspiration biopsy in the management of patients with thyroid nodules.

Fine-needle aspiration biopsy (FNAB) of the thyroid gland is the most cost-effective examination in the evaluation of thyroid nodules. The aim of this study was to present our experience from all patients who underwent thyroid FNA in the University Hospital of Ioannina, Greece, in the period 1993-2003, and its value in the diagnostic management of patients with thyroid nodules. FNA was performed in 900 patients of whom 753 were females and 147 males. The cases were classified according to diagnosis into five groups: benign/negative 628, primary carcinoma 28, metastatic carcinoma 5, suspicious/indeterminate 60 and non-diagnostic 179. Cytological findings were compared with histopathological findings and the statistical analysis in our data yielded the following results: sensitivity 92.1%, specificity 93.2%. These results are in accordance with the already published data in the international literature. In cases of differential diagnosis between adenomatoid hyperplasia and follicular neoplasia, four cases were diagnosed as hot nodules. In the benign group, three cases were diagnosed as nodular hyperplasia with cystic degeneration on FNA, but, after surgical treatment, histologically were diagnosed as papillary carcinomas. In the group of suspicious/indeterminate, two cases were diagnosed as suspicious for follicular neoplasia on FNA and, after surgical treatment, were diagnosed histopathologically as medullary carcinomas. In conclusion, we suggest that routine measurement of serum calcitonin is useful and mandatory in the detection of medullary carcinoma among patients with nodular thyroid diseases. Taking into consideration the clinical data can minimize false-positive and false-negative rates. We conclude that FNA is an effective screening test in the evaluation of the necessity for surgical treatment in patients with thyroid nodules.

Immunohistochemical study of extracellular matrix components in epiretinal membranes of vitreoproliferative retinopathy and proliferative diabetic retinopathy.

PURPOSE: The migration, proliferation, differentiation, and adhesion of cells and other cellular functions are influenced by the surrounding extracellular matrix in normal and wound healing conditions. The formation of epiretinal membranes, a wound healing process, is a serious complication of retinal diseases, the most important being proliferative diabetic retinopathy (PDR) and proliferative vitreoretinopathy (PVR). In the present study, the authors investigated the expression of various extracellular matrix components and in particular tenascin, fibronectin, laminin, collagen IV, and MMP-3 glycoprotein as well as the expression of glial fibrillary acidic protein in each type of epithelial membrane in order to elucidate the role of these molecules in the formation of these two types of membranes. METHODS: The authors performed immunohistochemistry in 14 PVR and 14 PDR membranes, using antibodies against the above mentioned extracellular matrix components. Tenascin and fibronectin were observed as major components in the extracellular matrix, while laminin and collagen type IV were detected as minor components in both types of membranes. A higher fibronectin expression in PVR compared with PDR membranes was found (p=0.0035). A positive relationship of its expression with the proliferative activity (p=0.15) and collagen type IV expression (p<0.0001) was also observed. RESULTS: Tenascin expression was positively correlated with glial fibrillary acidic protein positive cells in PDR membranes (p=0.04). Collagen type IV localized around vessels was observed with high levels in PDR membranes (p=0.0031). CONCLUSIONS: The results indicated that the extracellular matrix components seem to be involved in PVR and PDR, contributing to tissue remodeling and perhaps by different pathogenetic pathways, which could reflect different stages of development in these two types of membranes.

FNAC: its role, limitations and perspective in the preoperative diagnosis of breast cancer.

Fine-needle aspiration cytology (FNAC) was first described and performed in 1930. Thirty years later, it gained acceptance first in Europe and about a decade later in North America. The method is generally considered as a rapid, reliable, safe diagnostic tool to distinguish non-neoplastic from neoplastic breast lesions. In developed countries, in the last 20 years, mammographic screening programmes, which have been used extensively, are designed to detect the earliest possible breast cancer. The FNAC report is extremely important because it gives the necessary information for the management of patients, in order to proceed with more invasive diagnostic methods or surgical treatment, and to decide what kind of operation to perform. In the preoperative phase, FNAC has taken a fundamental role of both palpable and nonpalpable lesions, using ultrasound or stereotactic guidance. New developed techniques, breast biopsy instrumentation (ABBI) and mammotome have the advantage of complete removal of breast lesions, but this is not possible in all the examined cases. In developing countries, economical restrictions, low budget for health care and screening programmes put the patients at a disadvantage because of the high cost of sophisticated diagnostic methods, thus we recommend that FNAC be used as a routine diagnostic method because of its low cost compared with the others and this policy maximizes the availability of health care to women with breast cancer. We conclude that FNAC plays an important and essential role in the management of patients with breast lesions and also offers a great potential for prediction of patient outcome, disease response to therapy and assessment of risk of developing breast cancer. The reliability and efficiency of the method depends on the quality of the samples and the experience of the medical staff that performs the aspiration.

Immunohistochemical expression of extracellular matrix components tenascin, fibronectin, collagen type IV and laminin in breast cancer: their prognostic value and role in tumour invasion and progression.

The immunohistochemical expression of the extracellular matrix (ECM) components tenascin (TN), fibronectin (FN), collagen type IV (Coll) and laminin (LN), and their possible relationships were studied in a series of 134 operable breast cancer cases. Their expression was also compared with the expression of the proteolytic enzyme cathepsin D (CD), the adhesion molecule CD44 standard form (CD44s) and other known factors to clarify the prognostic value and role of these molecules in tumour progression and metastasis. TN expression in the tumour stroma was positively correlated with tumour grade and size, CD44s expression, tumour and stromal CD expression as well as with FN, laminin and Coll expression in the same areas. TN expression was inverse correlated with ER status. Its expression at the invasion front was only positively correlated with the lymph node status. Survival analysis showed an increased mortality risk associated with high levels of TN expression. In multivariate analysis, among the ECM proteins, only TN expression was independently correlated with patients' survival. FN expression was positively correlated with lymph node involvement, with the proliferation-associated index Ki-67 and stromal CD expression. Survival analysis showed an increased mortality risk associated with a high level of FN expression. Coll expression was positively correlated with the tumour size and LN expression. An inverse relationship of Coll expression with ER and PgR receptor status was also found. LN expression was positively correlated with tumour and stromal CD expression, with the proliferation-associated index Ki-67 and inversely with ER receptor status. The observed alterations in the expression of ECM proteins in breast cancer tissue and their correlations with the proteolytic enzyme CD and the adhesion molecule CD44s, suggest an involvement in cancer progression. In addition, overexpression of stromal TN and FN seems to have negative prognostic value in breast cancer patients.

Enhancement of the antineoplastic effect of anticarcinogens on benzo[a]pyrene-treated Wistar rats, in relation to their number and biological activity.

Naturally occurring anticarcinogens, such as vitamins C and E, and the microelement selenium were found to inhibit the induction of benzo[a]pyrene-induced malignant tumors in Wistar rats to various extends. The antineoplastic effect of the tested anticarcinogens is gradually increased according to the number of inhibitors selected. To date the maximum action against malignancy is manifested by use of the above three inhibitors. In the group of rats receiving vitamins C, E and selenium, the prolongation of life induced by adding more than one anticarcinogen to the treatment regime reached, and in some cases surpassed, the normal life expectancy of the rats. It is expected that by adding even more anticarcinogens, the antineoplastic potency (Ap) of the inhibitors will be further improved. These results encouraged us to conduct a clinical trial in terminal human cancer cases, in conjunction with the usual treatments of surgery or chemotherapy and irradiation.

Mutational activation of k-ras oncogene in human breast-tumors.

ras genes are thought to play an important role in human cancer since they have been found to be activated frequently in several types of human tumors. From preliminary studies it has been found however, that ras mutations are extremely rare in breast tumors and therefore it was of interest to examine the frequency of such mutations. In this study we examined 65 cases of primary breast carcinomas from paraffin blocks, for the presence of point mutations in codons 12 of the K-ras and H-ras genes. The polymerase chain reaction (PCR) technique was used to amplify a codon 12 containing 157 bp and a 312 bp region of the K-ras and the H-ras genes respectively, followed by restriction fragment length polymorphism (RFLP) analysis to identify the point mutations. Eight out of the 65 tumors (12.3%) were found to carry a K-ras mutation in codon 12 but none was found to carry a H-ras mutation. It is suggested that the mutational activation of the K-ras gene may be involved in the development of a small percentage of breast tumors.

Chondrosarcoma of the thumb: an unusual case with lung and cutaneous metastases and death of the patient 6 years after treatment.

An unusual case of a chondrosarcoma developed in the proximal phalanx of the thumb is described. Although the diagnosis of the malignancy was made preoperatively and the finger was amputated without any delay, the tumor metastasized widely and killed the patient 6 years later.

Mammary carcinoma with osteoclast-like giant cells. A study of eight cases with follow-up data.

Eight cases of a rare, distinctive variant of infiltrating mammary carcinoma featuring benign multinucleated osteoclast-like giant cells are reported. The multinucleated osteoclast-like giant cells are reported. The multinucleated giant cells were associated with ductal carcinoma in five cases and with infiltrating lobular carcinoma in three cases. Although three patients had lymph nodal metastases in level one, none of the nodal metastases contained giant cells. From the limited follow-up data of this report, it seems likely that the prognosis for patients who have this type of adenocarcinoma is not especially favorable. The observation that the giant cells generally occurred in areas of prominent angiogenesis suggests that the angiogenesis may be induced by some chemical substance produced by the tumor cells. Biochemical and immunologic investigations may eventually provide an explanation for this unusual morphologic manifestation of host reaction to mammary carcinoma.

p63 expression in benign and malignant breast lesions.

The p63 gene encodes six protein isoforms. The transactivating isoforms have similar actions with p53, while the N-isoforms inhibit transcription activation by p53 and transactivating isoforms. p63 is expressed in stratified epithelia and in basal cells of the prostate and salivary glands. In mammary epithelium p63 has been shown to be expressed only in the myoepithelial layer. In the present study we investigated the immunohistochemical expression of p63, in benign and malignant breast lesions, and compared it with known myoepithelial cell markers. Our material consisted of 140 benign and 126 malignant breast lesions. We used the antibodies anti-p63, anti-alpha-smooth muscle actin, anti-S-100 protein and anti-cytokeratin 14. In all benign lesions, p63 immunoreactivity was noted in the myoepithelial cell layer surrounding the luminal epithelial cells. A less continuous peripheral rim of myoepithelial cells was also highlighted with p63-staining in all situ carcinomas. All invasive breast carcinomas were devoided of peripheral p63 staining. Interestingly, strong nuclear p63 immunoreactivity was noted in a small fraction (5-15%) of epithelial cells in all cases of papillomatosis, in 62.5% of in situ ductal papillary-type carcinomas and in 33.3% of invasive papillary carcinomas. Comparable staining was observed with S-100. The stromal cells were unreactive to p63. Our findings suggest that p63 is a sensitive and specific myoepithelial marker, and may be included in immunohistochemical panels aiming to identify myoepithelial cells in problematic breast lesions. Regarding papillary neoplasms, it is possible that tumor cells acquire and exhibit at least in part a myoepithelial differentiation program.

Expression of vascular endothelial growth factor (VEGF) and association with microvessel density in small-cell and non-small-cell lung carcinomas.

Recent studies have demonstrated that tumor angiogenesis is a prognostic factor for various malignant neoplasms. Specifically, in non-small-cell lung carcinomas (NSCLCs) most reports show an association between neovascularization and vascular endothelial growth factor (VEGF) expression as well as the presence of metastases and survival, although a few reports do not agree with these findings. Angiogenesis is not clearly characterized in small-cell lung carcinomas (SCLCs), since they are rarely treated by surgery, and thus the available tissue for biological characterization is sparse. The aim of the present study was to investigate angiogenesis and the expression of VEGF in lung tumors. We examined 88 non-small-cell and 39 small-cell lung carcinomas. Angiogenesis was estimated by determining microvessel counts, with the use of anti-CD31 and anti-factor VIII antibodies and expression of VEGF was also evaluated immunohistochemically. Our data showed that in NSCLCs angiogenesis was more prominent in poorly-differentiated neoplasms and correlated with VEGF expression, therefore it is at least in part mediated by the latter. Interestingly, in SCLCs a higher vascularization was noted. However, there was no strong association with VEGF expression. Thus, small-cell lung carcinoma may represent a suitable neoplasm for testing antiangiogenic drugs in combination with chemotherapy. Nevertheless, antiangiogenic therapy should not be targeted specifically to the VEGF pathway, since in SCLCs other mediators of angiogenesis may be important as well.

Bcl-2 expression in colorectal tumours. Correlation with p53, mdm-2, Rb proteins and proliferation indices.

Immunostaining for bcl-2 protein was performed in 27 colorectal adenomas and 108 colorectal adenocarcinomas. The aim of the study was to determine bcl-2 expression in correlation with p53, mdm-2 and Rb expression, with proliferation indices (Ki-67-LI, PCNA-LI) as well as with conventional clinicopathological variables. A higher proportion of adenomas (30.8%) than carcinomas (16.7%) expressed bcl-2 and conversely, a lower proportion of adenomas (7.4%) than carcinomas expressed p53 (57.1%), the difference being statistically significant (p<0.0001). No correlation of bcl-2 expression with p53 expression (parallel or inverse) as well as with the other parameters studied was observed in any tumour. The bcl-2+/p53- subgroup of cancers showed a trend for correlation with negative lymph node status. Our data suggest, that bcl-2 expression may be involved in the early phase of colorectal carcinogenesis regardless of p53 status, while p53 function may be involved in a late stage of the adenoma-carcinoma sequence. P53 is apparently not involved in the regulation of apoptosis in the colorectal neoplasias or perhaps bcl-2 expression, as an early event in colorectal tumours, may occur before changes of p53 take place. Tumours with bcl-2+/p53- immunophenotype are frequently associated with negative lymph node status and seem to have a less aggressive behavior.

Immunohistochemical expression of retinoblastoma gene product (Rb), p53 protein, MDM2, c-erbB-2, HLA-DR and proliferation indices in human urinary bladder carcinoma.

Archival biopsy specimens from transitional cell bladder cancers (n=88) were analysed immunohistochemically for the expression of the retinoblastoma (Rb) gene protein, p53, mdm2, c-erbB-2, HLA-DR antigen and proliferation indices. An altered nuclear expression of Rb, p53 and mdm2 was observed in 55.2%, 33.3% and 18.2% of tumors respectively. Cytoplasmic membrane immunoreactivity (>25% tumor cells) for c-erbB-2 was detected in 14.1% of tumors and aberrant HLA-DR antigen cytoplasmic staining (>5% of tumor cells) in 22.2% of the cases. P53 overexpression was associated with higher tumor grade and stage. Aberrant HLA-DR antigen expression and PCNA were also correlated with the grade of differentiation and tumor stage. MIB1 was statistically correlated with stage. pRb scores and HLA-DR antigen expression were correlated with proliferation activity as determined by PCNA and MIB1 immunostaining. p53 protein was also strongly correlated with the proliferation index PCNA. A strong correlation between PCNA and MIB1 (p<0.0001) was also found. In addition a statistically positive correlation between p53 and HLA-DR antigen expression was observed. Our data show that, although pRb and p53 protein expressions are not associated between them, they may contribute to the growth fraction of the bladder cancer. In addition, p53 and HLA-DR antigen expression could be indicators of aggressive behavior of bladder cancer.

Glycoprotein CD44 expression in benign, premalignant and malignant epithelial lesions of the larynx: an immunohistochemical study including correlation with Rb, p53, Ki-67 and PCNA.

CD44 is an integral membrane glycoprotein that has diverse functions in cell-cell and cell-substrate interactions. It has been suggested that it may be a determinant of metastatic and invasive behavior in carcinomas. The immunohistochemical expression of CD44 was examined in a series of 34 squamous cell carcinomas, 13 in situ carcinomas, 35 cases with various degrees of epithelial dysplasia, 10 papillomas and 17 cases of keratosis. We used the monoclonal mouse anti-human phagocytic glycoprotein-1 CD44 (clone DF 1485), on formalin-fixed, paraffin-embedded tissue. CD44 expression was correlated with the expression of Rb and p53 proteins, with the proliferative indices Ki-67 and PCNA as well as with conventional clinicopathological data. The mean value of CD44 expression was 78.84 in squamous cell carcinomas, 78.04 in situ carcinomas, 54.93 in dysplasia, 26.8 in papillomas and 24.97 in keratosis. There was no significant difference of CD44 expression between in situ and invasive carcinomas. However, a strong difference of reaction between carcinomas and the other cases was observed. CD44 expression was statistically higher in dysplastic lesions than the cases of keratosis (p < 0.0001) and papillomas (p = 0.01). In the group of invasive carcinomas, CD44 expression was statistically correlated with pRb (p = 0.011), while in preinvasive lesions it was correlated with PCNA (p = 0.016). The relationship with the degree of dysplasia or grade of carcinoma and p53 protein expression was insignificant. These observations suggest that CD44 expression may be involved in the multiple mechanism of the development and progression of laryngeal lesions and may help to predict the risk of transformation of the benign or precancerous lesions to cancer.

Immunohistochemical expression of superoxide dismutase (MnSOD) anti-oxidant enzyme in invasive breast carcinoma.

The most important cellular protective mechanisms against oxidative stress are antioxidant enzymes. Their action is based on decomposal of reactive oxygen species (ROS) and their transformation to H2O2. Within the mitochondria manganese superoxide dismutase (MnSOD) affords the major defense against ROS. In this study we investigated tissue sections from 101 breast carcinomas for the immunohistochemical expression of MnSOD protein and these results were assessed in relation to various clinicopathological parameters, in order to clarify the prognostic value of this enzyme. The possible relationship to hormone receptor content, anti-apoptotic protein bcl-2, p53 and cell proliferation was also estimated. High expression levels were observed, as 79/101 (78,2%) cases expressed strong immunoreactivity. In this study MnSOD increased in a direct relationship with tumor grade and is therefore inversely correlated with differentiation (p=0.0004). Furthermore, there was a strong positive correlation between MnSOD expression and p53 protein immunoreactivity (p=0.0029). The prognostic impact of MnSOD expression in determining the risk of recurrence and overall survival with both univariate (long-rang test) and multivariate (Cox regression) methods of analysis was statistically not significant. These results indicate that neoplastic cells in breast carcinomas retain their capability to produce MnSOD and thus protected from the possible cellular damage provoked by reactive oxygen species. In addition, MnSOD content varies according to the degree of differentiation of breast carcinoma.

Immunohistochemical expression of the p53, mdm2, p21/Waf-1, Rb, p16, Ki67, cyclin D1, cyclin A and cyclin B1 proteins and apoptotic index in T-cell lymphomas.

Fifty-seven cases of T-cell lymphomas (TCL) including 5 lymphoblastic (T-LBL) and 52 peripheral TCL (PTCL) were analyzed by immunohistochemistry for the expression of p53, mdm2, p21, Rb, cyclin D1, cyclin A, cyclin B1, and Ki67/MIB1 proteins and 39/52 PTCL were also analyzed for the expression of p16 protein and for the presence of apoptotic cells by the TUNEL method. The aim was to search for abnormal immunoprofiles of p53 and Rb growth control pathways and to determine the proliferative activity and the apoptotic index of TCL. Abnormal overexpression of p53, p21 and mdm2, in comparison to normal lymph nodes, was found in 12/57, 10/57 and 2/57 cases of TCL, respectively. Abnormal loss of Rb and p16 expression was found in 1/57 and 2/39 cases, respectively, whereas abnormal overexpression of cyclin D1 was not detected in any of the 57 cases. Our data revealed entity-related p53/p21/mdm2 phenotypes. Indeed, most nodal and cutaneous CD30+ anaplastic large cell lymphomas (ALCL) showed concomitant overexpression of p53 and p21 proteins (7/8 cases), and mdm2 was overexpressed in 2 p53-positive nodal ALCL. In contrast, overexpression of p53 was found in 3/17 cases of nodal peripheral TCL unspecified (PTCL-UC) and 2/7 non-ALCL cutaneous pleomorphic TCL. Overexpression of p21 protein was detected in 2/3 p53-positive PTCL-UC and in 1/2 p53-positive non-ALCL cutaneous pleomorphic TCL. Finally, all the remaining 25 cases of TCL did not show p53 and p21 overexpression. Overall, the p53+/p21+ phenotype in 10/57 TCL suggests wild-type p53 capable of inducing p21 expression. The highest apoptotic index (AI) was found in ALCL and a positive correlation between apoptotic index and Ki67 index (p<0.001) was detected. Ki67, cyclin A and cyclin B1 expression was found in all 57 TCL and on the basis of the combined use of these 3 variables, 3 groups of proliferative activity could be determined: a) high in ALCL and T-LBL, b) low in mycosis fungoides (MF) and gammadelta hepatosplenic TCL, and c) intermediate in the remaining TCL entities. The proliferative activity in the 12 p53 overexpressing cases was higher in comparison to the 45 p53-negative cases. Ki67 expresion in more than 25% of tumour cells showed significant correlation with p53 overexpression (p<0.001). Rb expression tended to be parallel to Ki67, cyclin A and cyclin B1 expression in all but one case of nodal PTCL-UC which displayed loss of RB expression. Interestingly, this case was p53-negative, whereas the p53-positive cases were Rb-positive. These findings suggest that different pathogenetic routes may function in some TCL, involving either the p53 or, less frequently, the Rb pathways.