Milena Paglierani

Quantitative real-time reverse transcription polymerase chain reaction: normalization to rRNA or single housekeeping genes is inappropriate for human tissue biopsies ☆

Careful normalization is essential when using quantitative reverse transcription polymerase chain reaction assays to compare mRNA levels between biopsies from different individuals or cells undergoing different treatment. Generally this involves the use of internal controls, such as mRNA specified by a housekeeping gene, ribosomal RNA (rRNA), or accurately quantitated total RNA. The aim of this study was to compare these methods and determine which one can provide the most accurate and biologically relevant quantitative results. Our results show significant variation in the expression levels of 10 commonly used housekeeping genes and 18S rRNA, both between individuals and between biopsies taken from the same patient. Furthermore, in 23 breast cancers samples mRNA and protein levels of a regulated gene, vascular endothelial growth factor (VEGF), correlated only when normalized to total RNA, as did microvessel density. Finally, mRNA levels of VEGF and the most popular housekeeping gene, glyceraldehyde-3-phosphate dehydrogenase (GAPDH), were significantly correlated in the colon. Our results suggest that the use of internal standards comprising single housekeeping genes or rRNA is inappropriate for studies involving tissue biopsies.

Expression of matrix metalloproteinase 1, matrix metalloproteinase 2, and matrix metalloproteinase 9 in carcinoma of the head and neck

Numerous reports have documented a direct involvement of matrix metalloproteinase (MMP) overexpression in the development and progression of head and neck squamous cell carcinoma (HNSCC). In this study, the authors examined whether the expression of MMPs in HNSCC is correlated with other steps involved in tumor growth and metastasis, like angiogenesis, activation the nitric oxide (NO) pathway, and alteration of the p53 tumor suppressor gene.

HERG potassium channels are more frequently expressed in human endometrial cancer as compared to non-cancerous endometrium

HERG K+channels, besides contributing to regulate cardiac and neuronal excitability, are preferentially expressed in tumour cell lines of different histogenesis, where their role in the development and maintenance of the neoplastic phenotype is under study. We show here that both herg gene and HERG protein are expressed with high frequency in primary human endometrial cancers, as compared to normal and hyperplastic endometrium. RT-PCR and immunohistochemistry, using specific anti-HERG antibodies developed in our laboratory, were applied to tissue specimens obtained from 18 endometrial cancers and 11 non-cancerous endometrial tissues. herg RNA and HERG protein are expressed in 67% and 82%, respectively, of cancerous, while in only 18% of non-cancerous tissues. In particular, no expression was found in endometrial hyperplasia. Moreover, electrophysiological experiments confirmed the presence of functioning HERG channels on the plasma membrane of tumour cells. On the whole, these data are the first demonstration of the presence of HERG channels in primary human neoplasias, and could candidate HERG as a potential tool capable of marking cancerous versus hyperplastic endometrial growth.

Application of a Filtration- and Isolation-by-Size Technique for the Detection of Circulating Tumor Cells in Cutaneous Melanoma

Analysis of circulating tumor cells (CTC) in the peripheral blood of cutaneous melanoma patients provides information on the metastatic process and potentially improves patient management. The isolation by size of epithelial tumor cells (ISET) is a direct method for CTC identification in which tumor cells are collected by filtration as a result of their large size. So far, ISET has been applied only to CTC detection from epithelial cancer patients, and the technique has never been applied to cutaneous melanoma patients. We herein investigated the presence of CTC by ISET in the peripheral blood of 140 subjects (87 with cutaneous melanomas, 10 subjects undergoing surgery for melanocytic nevi, 5 patients with non-melanoma skin tumors, and 38 healthy volunteers). The identification of the cells trapped in filters as CTC was supported by positivity for immunohistochemical markers and for tyrosinase mRNA by real-time RT-PCR. CTC were neither detected in the controls nor in the in situ melanoma group. In contrast, CTC were shown in 29% of patients with primary invasive melanoma and in 62.5% of metastatic melanoma patients (P<0.01). CTC detection correlated with the presence of mRNA tyrosinase in blood samples, assayed by real-time RT-PCR (P=0.001). CTC detection corroborated by suitable molecular characterization may assist in the identification and monitoring of more appropriate therapies in melanoma patients.

Evidence for differential expression of Notch receptors and their ligands in melanocytic nevi and cutaneous malignant melanoma

The Notch signaling has been implicated in the regulation of self-renewal of adult stem cells and differentiation of precursors along a specific cell lineage, in normal embryonic development and organogenesis. There is also evidence that signaling through Notch receptors regulate cell proliferation and cell survival in several types of cancer, with opposing results depending on tissue context. No data are available in the literature concerning modulation of the expression of Notch receptors, and their ligands, in human cutaneous malignant melanoma. Here, we have investigated, for the first time, the expression of Notch-1, Notch-2, Jagged-1, Jagged-2 and Delta-like 1 proteins, by immunohistochemistry, in a series of benign and malignant human melanocytic lesions: five common melanocytic nevi, five ‘dysplastic nevi’ and 20 melanomas (five in situ, five T1–T2, five T3–T4 and five metastatic melanomas). We found that the expression of Notch-1 and Notch-2, as well as Notch ligands, was upregulated in ‘dysplastic nevi’ and melanomas as compared with common melanocytic nevi. These results indicate that the activation of Notch may represent an early event in melanocytic tumor growth and upregulation of Notch signaling may sustain tumor progression.

Sinonasal undifferentiated carcinoma, nasopharyngeal-type undifferentiated carcinoma, and keratinizing and nonkeratinizing squamous cell carcinoma express different cytokeratin patterns.

Sinonasal undifferentiated carcinoma (SNUC) is a highly aggressive malignant neoplasm that is often difficult to distinguish from other poorly differentiated carcinomas arising in the sinonasal tract. To search for a differential cytokeratin (CK) expression that could be useful for diagnostic purposes, we compared the expression of a large panel of CKs in a series of 6 SNUCs, 10 poorly differentiated squamous cell carcinomas (SCCs), 10 nonkeratinizing squamous cell carcinomas (NKSCCs), and 5 nasopharyngeal-type undifferentiated carcinomas (NPTCs). SCC, NKSCC, and NPTC frequently showed immunoreactivity for CK5/CK6, CK8, CK13, and CK19. In addition, SCC and NKSCC expressed CK14, which was not detected in NPTC, and SCC expressed CK7 (60% of cases) and CK4 (30% of cases), which were absent in NKSCC and NPTC. Three NKSCCs were associated with a Schneiderian papilloma, and the results of the immunostaining were similar in the two components, with the exception of CK4 and CK7, which were expressed by the papilloma and not by the carcinoma. In contrast to other carcinomas, SNUC was characterized by the exclusive expression of CKs of simple epithelia, such as CK8 (100% of cases), CK7 (50% of cases), and CK19 (50% of cases). Thus, there are significant differences in the pattern of CK expression between SNUC, SCC, NKSCC, and NPTC, which could be of diagnostic aid. Moreover, these findings support the hypothesis that SNUC is a separate entity from SCC and NPTC of the sinonasal tract.

Prognostic significance of c-erbB-2 expression in node negative breast cancer.

The prognostic value of c-erbB-2 oncogene expression was studied retrospectively in a consecutive series of 230 node negative breast cancers, followed-up for at least 7 years after primary treatment. The expression of c-erbB-2 oncoprotein was determined on formalin-fixed paraffin-embedded tissue, using a monoclonal anti-c-erbB-2 antibody by the avidin-biotin immunoperoxidase method. Positive immunostaining was observed in 20.9% of cases, whereas strong diffuse positivity was recorded only in 8.7% of cases. C-erbB-2 gene product showed no association to T category or nuclear grade. A significant association of c-erbB-2 expression to prognosis was observed only for cases showing a strong diffuse immunostaining, but such an association was no longer statistically significant at multivariate analysis adjusting for other prognostic factors such as T category and nuclear grading. C-erbB-2 expression is of no value to predict the clinical course of node negative patients in the current practice.

Development of bioengineered human larynx.

To date, only two human laryngeal allotransplants have been reported and, although they were successful, both patients required life-long immunosuppression. A bioengineered human larynx could represent a possible alternative to allotransplantation. Human larynxes were decellularized enzymatically to obtain acellular matrices. Histological and molecular analysis demonstrated that all cellular components and nuclear material were removed. SEM showed that decellularized matrices retained the hierarchical structures of the native larynx, and mechanical tests demonstrated that the decellularization did not significantly impaired the biomechanically properties of the obtained matrices. Immunohistochemical staining found residual angiogenic factors after decellularization, and CAM analysis demonstrated that acellular laryngeal scaffolds induce a strong in vivo angiogenic response. Using a decellularization method, we are now able to obtain, in a short and clinically useful time, natural bioengineered laryngeal scaffolds which could be use for partial or total implantation in humans.

Inducible nitric oxide synthase expression in benign and malignant cutaneous melanocytic lesions.

Nitric oxide (NO) is synthesized by nitric oxide synthases (NOS) and plays an important role in tumour growth. In this study, inducible NOS (iNOS) expression was evaluated by immunohistochemistry in 34 melanocytic naevi (13 common melanocytic naevi, six Spitz naevi, and 15 so‐called ‘dysplastic naevi’), ten cutaneous melanomas in situ, 50 stage I invasive melanomas, and eight subcutaneous metastases of melanoma. In addition, four samples of melanocytic naevi and four samples of invasive melanomas were collected in order to perform western blot and northern blot analysis. By immunohistochemistry, melanocytic naevi never expressed iNOS. Among cases of melanoma in situ, two were negative, seven displayed staining in less than 20% of melanoma cells, and positivity was observed in 21–50% of melanoma cells in only one case. iNOS expression was detected in 46 out of 50 invasive melanomas (92%). Among these cases, 18 showed positivity in less than 20% of melanoma cells, 18 showed positivity in 21–50% of melanoma cells, and ten showed iNOS expression in more than 50% of cells. Statistical analysis revealed a significant difference in iNOS expression between melanocytic naevi and cutaneous melanomas (p<0.001). In addition, iNOS expression was significantly higher in invasive melanomas than in melanomas in situ (p=0.01). Among primary cutaneous melanomas, no significant correlation was found between iNOS expression and histopathological parameters (histotype, level, thickness and presence of regression/inflammatory infiltrate) and disease‐specific survival. In subcutaneous melanoma metastases, iNOS expression was diffuse in more than 50% of cells. Statistical analysis revealed that subcutaneous melanoma metastases showed greater iNOS immunoreactivity than invasive melanomas (p=0.02). Molecular analyses confirmed that iNOS mRNA and protein were highly expressed in melanoma samples. In conclusion, iNOS was constantly absent in melanocytic naevi, whereas it was frequently expressed in melanomas, with up‐regulation of the enzyme paralleling tumour progression. These data suggest that iNOS may play a role in the malignant transformation of melanocytes and in tumour growth. In addition, iNOS may be useful as an immunohistochemical marker for malignant melanocytic lesions. Copyright

Estrogen Receptor Expression in Cutaneous Melanoma A Real-Time Reverse Transcriptase-Polymerase Chain Reaction and Immunohistochemical Study

OBJECTIVE To evaluate estrogen receptor (ER) expression in human melanoma tissues and in the adjacent healthy skin with the aim of explaining whether the ERalpha:ERbeta expression ratio has a role in neoplastic progression. DESIGN Prospective study. SETTING Department of Dermatology, University of Florence, Florence, Italy. Patients Fourteen patients, 12 with cutaneous melanoma (6 women and 6 men) and 2 with melanocytic nevi (1 woman and 1 man). MAIN OUTCOME MEASURES Using quantitative reverse transcriptase-polymerase chain reaction and immunohistochemical analysis, we analyzed ERalpha and ERbeta messenger RNA (mRNA) and ERbeta protein expression in cutaneous melanoma and in the healthy skin surrounding the lesions. RESULTS All melanocytic lesions expressed detectable levels of ERalpha and ERbeta mRNA as well as ERbeta protein. Dividing melanoma cases into 2 groups according to Breslow thickness, we found lower ERalpha and ERbeta mRNA levels and lower ERbeta protein levels in thicker, more invasive tumors. CONCLUSIONS These observations suggest a role for ERs in the metastatic process of melanoma cells, pointing at the possibility of using ERbeta expression as a prognostic indicator of melanoma. The possibility of distinguishing proliferative melanomas, which are associated with dismal prognosis, from the so-called dormant melanomas opens up novel avenues in tailoring individual treatments, as already happens for other tumors.