Proteomic analysis in human breast cancer: identification of a characteristic protein expression profile of malignant breast epithelium.

Gene expression analysis has become a promising tool in predicting the clinical course of malignant disease and the response to antineoplastic therapy. Surprisingly, only little is known about the protein expression pattern of human tumors. Recent advances in proteomic analysis allow proteins of interest to be identified by their expression and/or modification pattern in 2-DE rather than using the traditional approach of translating gene expression data. To identify a proteomic pattern that is characteristic for malignant breast epithelium, we performed differential 2-DE analysis in sets of microdissected malignant breast epithelia and corresponding adjacent normal breast epithelia from five patients with invasive breast carcinoma. Thirty-two protein spots were found to be selectively regulated in malignant epithelium, and were subjected to MALDI-TOF and/or immunoblotting for protein identification. Thirteen of the identified proteins had previously not been associated with breast cancer. The validity of these findings was confirmed by literature review and immunohistochemistry for identified proteins in an independent cohort of 50 breast cancer specimens. We here describe, for the first time, a proteomic analysis of matched normal and malignant epithelia from invasive breast carcinomas. This strategy leads to a better understanding of oncogenesis at an operational level and helps to characterize the malignant phenotype of individual tumors, and thereby to identify novel targets for antineoplastic therapy.

Physical state and expression of HPV DNA in benign and dysplastic cervical tissue: different levels of viral integration are correlated with lesion grade.

OBJECTIVE: Human papillomavirus (HPV) infection is the most important event in the malignant transformation of human cervical epithelium. Several high-risk (HR-)HPV subtypes have been identified, which lead to CIN and subsequently to invasive carcinoma. The reason for this phenomenon is still unknown, but it seems to be related to the physical state of HPV DNA. METHODS: Digene HC II test was used to identify HR- and/or low-risk (LR-)HPV infections in cervical swabs of 275 women attending our clinic for routine cytological screening and/or colposcopy because of an abnormal Pap smear comprising low-grade squamous intraepithelial lesions (LGSIL) and high-grade SIL (HGSIL). Specific HR (16, 18, 31, 33, 52b, 58) and LR (6, 11) subtypes were characterized in cervical biopsies of 10 women with benign cellular changes and of 68 women with CIN I-III by the PCR-restriction enzyme method. The physical state of HPV DNA (episomal, mixed and integrated form) was analyzed by bi-dimensional (2D)-gel electrophoresis. In addition, mRNA expression of E6/E7 genes was analyzed by RT-PCR. Furthermore, the relative virus load was determined in nine selected cases. The physical state and transcriptional activity of HPV DNA were then correlated to histopathological results. RESULTS: LR-HPV infection [27 cases (9.8%)] and HR-HPV infection [121 cases (44%)] of cervical swabs were clearly correlated to the degree of SIL. Further HPV typing in cervical biopsies of 78 women showed that HPV6 and 11 were restricted to benign cellular changes, CIN I and II, whereas HPV16 and 18 were observed predominantly in CIN III/CIS (P=0.01). No clear distribution pattern was observed for HPV31, 33, 52b and 58. Expression of HPV E6 and E7 transcripts was uniformly correlated with the different physical state of HPV DNA. Analyzing the physical state of these HPV subtypes, HPV6 and 11 could only be detected as an episomal form, independent of SIL grade. In normal epithelium and in CIN I and II, HPV16 and 18 were exclusively found in the episomal form. In CIN III/CIS, 15 of 30 cases of HPV16 (50%) and 16 of 17 cases of HPV18 (94%) were exclusively integrated into the host genome. Like HPV16/18, HPV31, 33, 52b and 58 were also present in the episomal form in normal epithelium and in CIN I and II, but were integrated in 80% of the CIN III/CIS (4/5) cases. CONCLUSION: Absent integration of HPV16 DNA in some CIN III/CIS suggests that integration is not always required for progression early dysplastic lesions. In contrast, integration of HPV type 18 and others appears to be of major importance for the transforming efficacy of cervical dysplasia. The applied method represents a sensitive instrument to assess the physical state of HPV and is useful to predict the progression of disease.

Characteristics of clear cells and Toker cells in the epidermis of underlying nipple duct adenoma.

Clinically, it is difficult to differentiate between nipple duct adenomas (NDAs) and Paget's disease of the nipple. These lesions share similar morphological and histological characteristics. Clear cell types present in NDA, epidermal clear cells (ECC) and Toker cells (TC), share immunoreactive similarities to Paget cells which can lead to confusion in classification. The aim of this study was to obtain information on the characteristics and histogenesis of ECC and TC, to distinguish these cells from Paget cells. Ten nipple epidermal with NDA were compared to 25 histologically normal nipples. Samples were analyzed for cytokeratins (CKs) 7, 8 and 18, carcinoembryonic antigen (CEA), c-erbB-2/HER2 expression and human papillomavirus (HPV-) DNA. In 13 out of 25 normal nipples the staining sequence demonstrated that ECC and TC cell types are immunoreactive with CKs 7, 8 and 18 in the basal region of the epidermis. In contrast, aggregated CKs 7, 8 and 18-immunoreactive ECC and TC were identified in the epidermal of 8 of the 10 NDA cases. In 2 cases, TC were continuous with the underlying NDA, suggesting that TC might be of ductal origin and migrate through the galactophorous ostia. In NDAs and 25 histologically normal nipples, ECC and TC were negative for CEA, c-erbB-2/HER2 and HPV-DNA. ECC and TC, normally present in the nipple epidermis, may proliferate and form aggregates in the presence of an underlying NDA. These cells show immunoreactivity for CKs 7, 8 and 18 but are negative for c-erbB-2/HER2, CEA and HPV-DNA and should not lead to the mistaken diagnosis of Paget's disease.