Overexpression of vimentin in canine prostatic carcinoma

Canine prostatic tumours exhibit similarities to those of man and may represent a useful model system to explore the mechanisms of cancer progression. Tumour progression to malignancy requires a change from an epithelial phenotype to a fibroblastic or mesenchymal phenotype. Vimentin expression is associated with the invasive phenotype of human prostate cancer cells. The aim of the present study was to characterize immunohistochemically the expression of vimentin by canine prostatic carcinomas. Primary carcinomas and metastatic tumour foci both showed vimentin expression. This finding suggests that the acquisition of the epithelial–mesenchymal transition phenotype in canine prostatic carcinoma may be characterized by the presence of mesenchymal intermediate filament (vimentin) that could lead to a higher likelihood of metastasis.     

Vimentin and cytokeratin expression in nodular hyperplasia and carcinoma of the prostate.

AIM--To assess the value of vimentin and cytokeratin (CK) intermediate filament proteins (IFPs) in distinguishing between nodular hyperplasia and carcinoma of the prostate and in predicting prognosis in prostatic cancer. METHODS--Fifteen carcinomas and 49 cases of nodular hyperplasia were studied using frozen sections and monoclonal antibodies to CK and vimentin IFPs. RESULTS--There was no statistically significant difference in vimentin expression between nodular hyperplasia and carcinoma. The luminal epithelium in both also reacted with antibodies which detect CK8, 18 and 19. CK 7 expression was found in 57% of cases of nodular hyperplasia and was not identified in any carcinoma. There was a reaction with antibodies to CK1, 2, 3, 4, 10, 11, and 13 in only a minority of cases. There was no statistically significant difference in vimentin and CK reactivity in high and low grade carcinomas. CONCLUSION--Neither vimentin nor CK expression assists in establishing whether a prostatic lesion is benign or malignant or in predicting the biological behaviour of a prostatic carcinoma.     

Expression of basal cell keratins in human prostate cancer metastases and cell lines.

Within normal human prostate epithelium, basal and luminal cells can be discriminated by their expression of keratins (K). While basal cells express K5/14, luminal cells show expression of K8/18 and an intermediate cell population can be identified by co-expression of K5/18. Prostate cancer is predominantly composed of luminal and neuroendocrine cells, while a minority of cells have a basal phenotype. In order to distinguish between basal and intermediate cells, and to assess the effects of androgen deprivation on prostate cancer, 56 human prostate cancer metastases and three cancer cell lines were characterized using antibodies to K5, K14, K18, and the neuroendocrine marker chromogranin A (ChA). The staining was performed on paraffin tissue and visualized by the avidin-biotin-peroxidase complex method. Protein expression was quantified as the number of positive cells in 20 high power fields (HPF; 400x). Keratin expression in the prostate cancer cell lines LNCaP, DU145, and PC3 was analysed by immunofluorescence with triple staining and confocal laser scanning microscopy. Prostate cancer metastases were consistently positive for K18 and negative for K14, irrespective of hormonal therapy. K5 expression was displayed in 28.9% of the tumours without treatment, in 75% after androgen deprivation, and in 57.1% of hormone-escaped prostate carcinomas. After androgen deprivation, the number of K5-expressing cells increased significantly. While androgen-dependent prostate cancer showed a median of 0 cells/20 HPF (range 0-50), regressed tumours displayed 22.5 (range 0-65) and hormone-escaped tumours 7.5 (range 0-361) positive cells/20 HPF. Expression of ChA was observed in 47.4% of the androgen-dependent tumours. The number of neuroendocrine cells was not significantly affected in regressed or hormone-escaped disease. The androgen-dependent cell line LNCaP stained for K18, while the androgen-independent lines DU145 and PC3 both expressed K5 and 18. Expression of K5 in the absence of K14 identifies the existence of an intermediate cell population in prostate carcinoma. Accumulation of intermediate cells in regressed and hormone-escaped prostate cancer indicates that for their survival, these cells are androgen-independent.     

Heterogeneity and co-expression of intermediate filament proteins in adenoid cystic carcinoma of salivary glands.

Among a series of 76 adenoid cystic carcinomas (ACC), 51 cases with cibriform or trabecular patterns were selected for an immunohistochemical study. These tumors were composed of three types of cells: basaloid, myoepithelial and ductal luminal acinous or tubular cells with a variable amount of each cell type from one case to another. Monoclonal antibodies (MoAb) against keratins (PKK1, KL1, K8.12, K8.13, K4.62 anti-cytokeratins antibodies) and against vimentin were used. Tubular cells were characteristically marked by anti-cytokeratins MoAb, but with a great heterogeneity of keratin distribution. In myoepithelial cells, keratin was absent or slightly positive and vimentin was present, with co-expression of the two types of filaments in some cells. Like myoepithelial cells, basaloid cells were positive to anti-vimentin antibody and negative or slightly positive to anti-keratin antibodies, with sometimes a co-expression of vimentin and keratin filaments in the same cell. Histogenesis of adenoid cystic carcinomas was discussed. Progenitor intercalated duct reserve cells may change into ductal luminal and myoepithelial tumor cells. Otherwise, basaloid cells, arising also from intercalated duct reserve cells, are able to acquire some secretory organites.     

The cytokeratin profile of medullary carcinoma of the breast

AIMS: The cytokeratin (CK) phenotype and vimentin expression of 31 medullary carcinomas was studied using commercially available antibodies on archived material. Comparing the phenotype of typical and atypical tumours and the phenotype of metastases, the biological significance of cytokeratin and vimentin expression in medullary carcinomas of the breast was determined. METHODS AND RESULTS: Antibodies to CK4, CK5 and 6, CK7, CK14, CK8 and 18, CK19, CK20 and to vimentin were used. All the typical and atypical medullary carcinomas and the metastases (10 cases) stained negatively for CK4 and positively for CK8-18 (CAM5.2). Almost all the tumours were CK7 and CK19 positive and CK20 negative. Twelve per cent of the tumours contained CK14. Twenty-five per cent of the typical, 43% of the atypical and 20% of the metastatic medullary carcinomas showed CK5-6 positivity. No association between the cytokeratin-vimentin profile of the tumours and axillary node metastases, tumour size or oestrogen receptor status was found but instability of CK expression was demonstrated by comparing the primary tumours with their metastases. CONCLUSIONS: : Medullary carcinomas of the breast express all the glandular type CKs including CK19 and additionally a proportion of the tumours expresses some of the CKs typical for myoepithelial cells. There was no correlation with prognostic factors.     

Immunohistochemical reaction patterns of keratins in MNNG-induced shrew oesophageal carcinomas

The distribution of keratins in N-methyl-N'-nitro-N-nitrosoguanidine-induced oesophageal carcinomas in shrews was tested immunohistochemically, using a panel of seven different monoclonal antibodies. The studies were done on methacarn-fixed paraffin-embedded tissue, using the labelled streptavidin biotin method, and the relationship between morphological characteristics and keratin reaction patterns in carcinomas was analysed and compared with that in adjacent normal oesophageal epithelium. In the normal oesophageal epithelia, KL1, AE1, AE3, CK8.12 and CK4.62 stained suprabasal cells, 312C8-1 reacted to basal cells, and KS-1A3 labelled all epithelial cells. In squamous cell carcinomas, almost all the cancer cells were labelled strongly by 312C8-1 and weakly by KS-1A3, while a few cells in the centres of the keratinized foci were stained by KL1, AE1, AE3, CK8.12, and CK4.62. Like human oesophageal carcinomas, shrew oesophageal carcinomas maintain expression of human keratin 14, as determined by 312C8-1. The expression of human keratin 13, as determined by KS-1A3, was down-regulated.     

Immunohistochemical investigation of different cytokeratins and vimentin in the prostate from the fetal period up to adulthood and in prostate carcinoma

From the fetal period up to puberty the immature epithelium of the prostate glands, the prostatic ducts, the ejaculatory ducts and the seminal vesicles as well as the urothelium of the prostatic urethra are extensively positive for different keratin antibodies (antibody against keratins from human stratum corneum, broadly reacting antibody "AE1 and AE" and antibodies against the keratins 7, 8, 18 and 19) immunohistochemically. The epithelium of the ejaculatory ducts and seminal vesicles in addition regularly exprimates vimentin which is found in the epithelium of the prostate glands focally. During puberty, the immature epithelium of the prostate glands differentiates into the two cell types basal cell and secretory epithelium which differ immunohistochemically: Keratins from human stratum corneum are exclusively demonstrable in the basal cells, the keratins 8 and 18 only in the secretory epithelium. For keratin 7, 19 and the antibody "AE1 and AE3" both cell types are positive. Keratin 7 is demonstrable only focally. The secretory epithelium partly co-exprimates keratins and vimentin. Prostatic carcinomas of different grades virtually contain no keratins from stratum corneum. All other keratins are found in variable extension in the vast majority of the tumors independent of the differentiation. Vimentin is positive mostly focally in about 50% of the tumors. Prostatic carcinoma and the secretory epithelium of the prostate glands share identical immunohistochemical features and differ from the basal cell by several markers. This indicates that prostatic carcinoma rather derives directly from the secretory epithelium than from the basal cell.     

Differential expression of cytokeratin mRNA and protein in normal prostate, prostatic intraepithelial neoplasia, and invasive carcinoma.

The expression of cytokeratin (CK) mRNA for CK5, -8, -14, -16, and -19 was investigated in normal prostate, prostatic intraepithelial neoplasia (PIN) lesions, and invasive carcinoma using in situ hybridization. Protein localization was carried out in adjacent sections using immunohistochemistry and correlated with mRNA expression. Snap-frozen human prostate samples including 22 examples of normal glands, 20 cases of PIN lesions, and 12 cases of invasive carcinoma were examined. CK5 and -14 mRNA and protein were prominently expressed only in the basal cells of normal glands and PIN lesions. CK14 mRNA was absent in the luminal cells of the most of the PIN lesions but was seen at a low level in some PIN lesions. CK14 protein was not detected in any PIN lesion, suggesting that, if the cell that makes up the PIN lesions is derived from a basal cell, CK14 translation is depressed although a low level of CK14 mRNA may persist. CK8 mRNA and protein were constitutively expressed in all epithelia of normal and abnormal prostate tissues. CK19 mRNA and protein were persistently expressed in both basal and luminal cells of the tubular portion of normal glands as well as PIN lesions, but were expressed heterogeneously in both basal and luminal cells of normal alveoli. CK16 mRNA was expressed in a similar pattern as CK19, but CK16 protein was not detected either in normal or in abnormal prostate tissues. In conclusion, the expression of CK19 in PIN lesions is similar to its tubular expression and would support an origin of PIN lesions from this structure rather than the alveolar portion of the glands. The similar cytokeratin expression between PIN lesions and invasive carcinoma further supports the concept that PIN is a precursor lesion of invasive carcinoma.     

Cytokeratin profiles of male breast cancers

AIMS: The prognostic factors and expression of molecular markers in male breast carcinomas are similar to those in female breast cancers. The identification of distinct cytokeratin (CK) profiles (basal as opposed to luminal cells) helps to identify subsets of tumours with different clinical behaviour. The aim of this study was to investigate CK expression in male breast cancer. METHODS AND RESULTS: Thirty-two cases of male breast cancer were studied. The panel of CKs studied by immunohistochemistry included: 5/6, 14, 17, 18 and 19. Pathological findings and CK expression were analysed in all cases. Histological patterns included ductal carcinoma in situ, invasive ductal carcinoma and mixed patterns. Four cases were positive for CK5/6 and CK14, identifying a basal-like phenotype. CK17 was negative in all but two cases. All cases expressing either CK5/6 or CK14 were invasive carcinomas of high nuclear and histological grade and were also larger compared with the tumours not expressing CK5/6 and CK14. All tumours except three (also negative for CK5/6) expressed CK18 and CK19. The four basal-like tumours were negative for Her-2 expression. CONCLUSIONS: Male breast carcinomas have a basal-like phenotype that is similar in frequency to that of female breast carcinomas. The expression of CK5/6 and CK14 identifies a subset of pathologically aggressive male breast cancers.     

Co-expression of cytokeratin and vimentin intermediate-sized filaments in renal cell carcinomas

Summary The expression of intermediate-sized filaments (IF) was examined by immunocytochemical methods in 40 primary renal cell carcinomas and compared with the IF distribution in the normal adult human kidney. All tumours stained positively with cytokeratin IF antibodies. Co-expression of cytokeratins and vimentin was observed in 21/40 (52,5%) renal carcinomas. Double immunofluorescence labelling demonstrated that in most of these cases tumour cells contained both cytokeratin and vimentin type IF. In normal human kidneys, cells of the various tubular segments disclosed a positive reaction with cytokeratin antibodies in a different intensity and intracellular localization. Co-expression of cytokeratin and vimentin IF in normal adult human kidneys has never been observed. From a histogenetic point of view, co-expression of cytokeratins and vimentin in renal cell carcinoma obviously represents an atavistic phenomenon since vimentin is re-expressed by these tumour cells during neoplastic transformation. This finding indicates the metanephric origin of the renal parenchyma. In surgical pathology the possibility of very rare co-expression of cytokeratin and vimentin IF within tumour cells should be considered, particularly in the differential diagnosis of clear cell carcinomas.Dedicated to Prof. Dr. K. Goerttler on the occasion of his 60th birthday     

Keratin profiles in normal/hyperplastic prostates and prostate carcinoma

Summary Immunoreactivities in 25 cases of prostatic adenocarcinoma and 10 normal/hyperplastic prostates were investigated in methacarn-fixed, paraffin-embedded serial sections using a panel of nine anti-keratin monoclonal antibodies (mAbs); 34 E12, CK8.12, 312C8-1, CK4.62, RPN1165, RPN1162, 35H11, CK5, M20, and one of anti-actin mAb, HHF35. In normal/ hyperplastic prostates, RPN1162, 35H11, CK5 and M20 stained luminal cells without staining basal cells, and 34E12, CK8.12 and 312C8-1 stained basal cells but not luminal cells. Other mAbs, CK4.62 and RPN1165, stained basal cells as well as luminal cells. All of the mAbs labelling luminal cells stained cancer cells with variable frequencies in a manner unrelated to the grade of tumour differentiation. Of the prostate cancer cases 92% were scored positive with M20, 84% with 35H11, 80% with CK5, 68% with CK4.62, 60% with RPN1165 and 4% with RPN1162. However, basal cell-specific keratins labelled with 34E12, CK8.12 and 312C8-1 were totally negative in the cancer cells. HHF35 showed no labelling in normal, hyperplastic or neoplastic epithelial cells of the prostate. Our findings indicate that the major part of the cells of prostatic adenocarcinomas have keratin phenotypes similar to luminal cells but not basal cells, and that no myoepithelial differentiation can be detected in epithelial cell of the prostate. Thus, mAbs for keratins facilitate the identification of epithelial cell phenotypes in normal, benign and malignant conditions of the prostate.     

The distribution of oestrogen receptors in normal, hyperplastic and neoplastic canine prostate, as demonstrated immunohistochemically

The role of oestrogens and their receptors (ERs) in prostatic growth and differentiation and in the progression of prostatic carcinoma has been well investigated in human medicine. In dogs, however, available reports on the expression of ERs in normal, hyperplastic or neoplastic prostates are few and controversial, or completely lacking. Three normal, three hyperplastic and nine neoplastic canine prostates were examined histologically, and immunohistochemically with a polyclonal antibody directed against human ERs. Evaluation of the percentage of immunolabelled cells was performed by digital image analysis. The study showed that ERs were expressed in the nuclei of epithelial and stromal cells in normal, hyperplastic and neoplastic prostates. All nuclei in normal and hyperplastic prostates were strongly and homogeneously immunolabelled by the antibody used. However, the percentages of immunolabelled nuclei in the nine prostatic carcinomas were greatly reduced, ranging from 36.34% to 66.73%. The severe loss of ER expression in canine prostatic carcinomas may account for the relative lack of differentiation of these tumours in the dog.     

HOXB13 is a sensitive and specific marker of prostate cells, useful in distinguishing between carcinomas of prostatic and urothelial origin

The origin of a primary or metastatic carcinoma in the pelvic area is sometimes difficult to establish, in particular the distinction between those originating in the bladder and the prostate. A candidate marker is the HOXB13 gene, essential for prostate development. Some studies have shown expression of HOXB13 protein by immunohistochemistry in the nuclear compartment of benign prostate luminal epithelium and prostate carcinoma. Forty-two cases of biopsies and resection specimens of the prostate and urinary bladder, metastatic lymph nodes, and pelvic masses were retrieved from our databases. In all cases, doubt persisted regarding prostatic versus urothelial origin. All cases were stained for CK7, p63, p504s, PSA, CK20, and HOXB13. Chromogranin A, CD56, and synaptophysin were used when neuroendocrine differentiation was suspected. HOXB13 staining was negative or only weakly positive in all carcinomas of urothelial origin. Three of four carcinomas with neuroendocrine differentiation did not express HOXB13. The fourth carcinoma, in a patient with a history of prostate carcinoma, was positive. In two cases with a synchronous prostatic and urothelial carcinoma, HOXB13 was exclusively expressed in the prostatic carcinoma. Our results demonstrate that HOXB13 expression identifies prostatic origin of a carcinoma with good sensitivity (89 %) and very good specificity (100 %). HOXB13 is a specific and sensitive marker for prostate cells and a valuable diagnostic tool, especially when poorly differentiated or neuroendocrine tumors are encountered. These results justify testing of HOXB13 as a prostate-specific carcinoma marker in larger cohorts for a more thorough evaluation of its sensitivity and specificity.     

Identification of molecular phenotypes in canine mammary carcinomas with clinical implications: application of the human classification

Similarly to humans, canine mammary cancer represents a heterogeneous group in terms of morphology and biological behaviour. In the present study, we evaluated a series of canine mammary carcinomas based on a new human classification, initially based on gene expression profiling analysis. Similarly to human breast cancer, by using an immunohistochemistry surrogate panel based on five molecular markers [estrogen receptor, human epidermal growth factor receptor 2 (HER2), cytokeratin 5, p63 and P-cadherin], we were able to classify canine mammary carcinomas into four different subtypes: luminal A [estrogen receptor (ER)+/HER2-; 44.8%], luminal B (ER+/HER2+; 13.5%), basal (ER-/HER2- and a basal marker positive; 29.2%) and HER2 overexpressing tumours (ER-/HER2+; 8.3%). Luminal A-type tumours were characterised by lower grade and proliferation rate, whereas basal-type tumours were mostly high grade, high proliferative and positive for cytokeratin 5, p63 and P-cadherin. In addition, as in humans, basal subtype was significantly associated with shorter disease-free and overall survival rates, and we propose canine mammary carcinomas as a suitable natural model for the study of this particular subset of human carcinomas.     

Expression of cytokeratins in the epithelium of canine odontogenic tumours

Odontogenic tumours are considered to be relatively rare; however, several histologically distinct types have been identified in dogs. The more common canine odontogenic tumours are peripheral odontogenic fibroma and canine acanthomatous ameloblastoma. The expression of cytokeratins (CKs) has been established for the human dental germ and odontogenic tumours. The aim of the present study was to describe the immunohistochemical expression of a panel of CKs in the epithelium of the canine dental germ, normal gingiva and odontogenic tumours arising in this species. Samples from 20 odontogenic tumours, 12 tooth germs and three normal gingival tissues were obtained. Each sample was stained with haematoxylin and eosin and subjected to immunohistochemistry for CK expression. The typical expression pattern of CKs in the odontogenic epithelium and gingiva of dogs was CK14 and CK5/6. CKs 7, 8, 18 and 20 were generally absent from the canine dental germ, gingiva and odontogenic tumours. Dogs and man therefore exhibit similar CK expression in the odontogenic epithelium.     

Vimentin expression in benign and malignant breast epithelium.

AIMS--To determine vimentin expression in epithelial cells in benign breast disease and malignant breast tumours; to assess the value of vimentin expression as a prognostic indicator in breast carcinoma. METHODS--Frozen and formalin fixed, paraffin wax embedded sections from 78 carcinomas, three phyllodes tumours, 19 fibroadenomas and 19 cases of fibrocystic disease were examined with a monoclonal antibody from the V9 clone. A correlation between vimentin expression and known prognostic indicators was sought in ductal carcinomas. The intracellular localisation of vimentin was examined in benign and malignant lesions. RESULTS--Vimentin expression was identified on frozen section in the cells of ductal (53%), lobular (86%), and mucinous (33%) carcinomas and in the luminal epithelium of fibroadenomas (68%), cases of fibrocystic disease (47%), and a malignant phyllodes tumour. Formalin fixation reduced the percentage of carcinomas and cases of benign disease in which vimentin was detected. This reduction was more pronounced in fibroadenoma and fibrocystic disease than in ductal carcinoma. Associations were identified between vimentin expression as detected on frozen section and tumour grade, size, number of lymph nodes affected, oestrogen receptor content and growth fraction. Only the association with grade was significant (p = 0.045). There was no significant correlation between any of these prognostic variables and vimentin expression on paraffin wax sections. There was no difference in the intracellular localisation of vimentin staining between benign and malignant lesions, or between low and high grade ductal carcinomas. CONCLUSION--There is some loss of vimentin immunoreactivity after formalin fixation. Vimentin expression does not assist in differentiating between benign and malignant breast disease, but is correlated with tumour grade in ductal carcinoma.     

CD44 expression is a feature of prostatic small cell carcinoma and distinguishes it from its mimickers

Small cell neuroendocrine carcinoma of the prostate is a rare variant of prostatic cancer that shares morphologic similarity with prostatic adenocarcinoma of Gleason 5 pattern. It has also been considered morphologically and immunohistochemically indistinguishable from small cell neuroendocrine carcinomas of other origins. CD44 is a cell-surface molecule proposed to identify cancer stem/progenitor cells in prostate cancer. We performed immunohistochemical study for CD44 expression in 11 cases of prostatic small cell neuroendocrine carcinoma and compared its patterns of expression with 73 cases of prostatic adenocarcinoma and 47 cases of small cell neuroendocrine carcinomas of other organs. Strong and diffuse membrane staining for CD44 was observed in 100% of the prostatic small cell neuroendocrine carcinomas. In conventional adenocarcinomas of the prostate, positive staining was only seen in rare, scattered tumor cells; and CD44 staining was negative in most of the small cell neuroendocrine carcinomas of nonprostate origin. The difference in CD44 expression between small cell neuroendocrine carcinomas of the prostate and those of other organs are statistically significant (P < .001). Our study demonstrates the utility of immunohistochemical staining for CD44 in distinguishing prostatic small cell neuroendocrine carcinoma from its mimickers including prostatic adenocarcinoma of Gleason 5 pattern and small cell neuroendocrine carcinomas of other organs. CD44 is the first marker that shows a high degree of tissue/organ specificity for small cell neuroendocrine carcinomas. Because CD44 is a putative marker of prostate cancer stem cells, the strong and diffuse expression of CD44 and the lack of expression of prostate luminal differentiation markers androgen receptor and prostatic specific antigen in prostatic small cell neuroendocrine carcinomas suggest that the tumor cells may retain cancer stem cell features.     

Immunohistochemical staining patterns of keratins in normal oesophageal epithelium and carcinoma of the oesophagus

To clarify the keratin staining patterns of invasive carcinoma of the oesophagus, 22 cases of formalin-fixed paraffin-embedded surgical specimens were examined immunohistochemically with the labelled streptavidin biotin method using a panel of six different monoclonal anti-keratin antibodies. The antibody reacted adequately when antigen was retrieved in a microwave oven, and the relationship between morphological characteristics and keratin reaction patterns was analyzed in carcinomas and compared with adjacent histologically normal epithelium. In the normal oesophageal epithelium, AE3 and CK8.12 labelled all layer of cells, KS-1A3, E3 and KL1 labelled suprabasal cells, and LL002 selectively labelled the basal cells. In squamous cell carcinomas, AE3, CK8.12, KL1 and LL002 labelled almost all the tumour cells regardless of their differentiation, E3 only labelled keratinized cells, while marked decrease or loss of KS-1A3 staining was seen in all cases examined. Therefore, the characteristic profile of squamous cell carcinoma was a strong and diffuse expression of keratin 14 and 16, strong but localized expression of keratin 17, and loss of keratin 13 expression. Undifferentiated carcinoma totally lacked all keratin reactivity. The findings suggested that the neoplastic epithelial cells showed different keratin reactivity and distribution compared to normal oesophageal epithelium. In addition, histologically normal epithelium, dysplasia and carcinoma-in-situ adjacent to or overlying carcinoma expressed keratin 14.     

DIFFERENTIATION PATHWAYS IN PRIMARY INVASIVE BREAST CARCINOMA AS SUGGESTED BY INTERMEDIATE FILAMENT AND BIOPATHOLOGICAL MARKER EXPRESSION

The expression of intermediate filament proteins (IFPs) in 65 primary breast carcinomas was analysed by a panel of specific antibodies. Results were integrated with the oestrogen and progesterone receptor (ER and PGR) status, Ki-67 marking, and epidermal growth factor receptor (EGFr) expression. Invasive breast carcinomas could be divided into three main groups: group 1 revealed positivity only for ‘simple epithelial’ cytokeratins (CKs 7, 8, 18, and 19); group 2 also stained with the antibodies K8.12 and 34βE12; while group 3 showed co-expression of CKs 14 and 17, vimentin, and α-smooth muscle actin. Group 3 consistently comprised tumours with the highest Ki-67 levels, EGFr positivity, and ER-PGR negative status. On the other hand, groups 1 and 2 usually exhibited a positive hormonal status, lower proliferative activity, and EGFr negativity. The results of this study indicate that the determination of IFPs can significantly contribute to the identification of groups of patients with different biopathological settings and possibly different clinical behaviour.     

Pleomorphic adenoma of the salivary gland in two dogs

Pleomorphic adenomas of the salivary gland were diagnosed in two dogs. The tumours were single, firm and well circumscribed, with a smooth cut surface. Metastatic tumours were not detected. Histopathological examination revealed that the tumours contained multiple cysts lined with luminal epithelial cells and myoepithelial cells, and mucinous, myxochondroid and cartilaginous tissues. Immunohistochemical examination demonstrated labelling of luminal epithelial cells and myoepithelial cells, and mucinous, myxochondroid and cartilaginous tissues with antibodies to cytokeratin LU-5, AE1/AE3, CK-14, CALP, a-SMA, vimentin, GFAP, and S-100. Labelling for GFAP indicated stromal transformation into myxoid and chondroid tissues.