TRAF4 overexpression is a common characteristic of human carcinomas

Tumor necrosis factor receptor (TNFR) associated factor 4 (TRAF4) was initially identified as a gene amplified and overexpressed in breast carcinomas. Our aim was to evaluate whether TRAF4 protein overexpression exists in other cancer types. Immunohistochemistry analysis of tumor samples from 623 patients with 20 different tumor types showed that TRAF4 was overexpressed in 268 tumors (43%), including 82 of 137 lung adenocarcinomas (60%). Interestingly, 32 primary tumors and their matching metastases exhibited mostly similar TRAF4 expression pattern. TRAF4 protein overexpression was limited to cancer cells and the subcellular localization was consistently cytoplasmic in a large majority of cases. To investigate changes in TRAF4 gene copy number, 125 cases from six different types of carcinomas were also analysed by fluorescence in situ hybridization. Out of the 28 cases (22%) showing an increased TRAF4 gene copy number, 23 (82%) were overexpressing the protein. Thus, TRAF4 gene amplification is one of the mechanisms responsible for TRAF4 protein overexpression in human cancers. Considering that TRAF4 is located at 17q11.2 in a region of amplification devoid of known oncogenes and is commonly overexpressed in cancer, our data support an oncogenic role for TRAF4.

Variable sensitivity and specificity of TTF-1 antibodies in lung metastatic adenocarcinoma of colorectal origin

Thyroid transcription factor-1 (TTF-1) is considered as a reliable marker for differential diagnosis in distinguishing primary adenocarcinomas of the lung from extrathoracic origins. We previously reported the first case of lung metastasis of colorectal origin, with nuclear expression of TTF-1. As most previous studies were performed on series of extrathoracic primary tumors, we raised the question of a possible role of lung microenviroment in TTF-1 expression. We investigated the rate of TTF-1 expression in lung metastases of extrathoracic adenocarcinomas and compared results of immunohistochemistry performed with different primary antibodies. Two different clones of antibodies (8G7G1/1 from Dako, SPT24 from Novocastra) raised against TTF-1 were used on 56 lung-metastatic malignant tumors, 41 from colorectal origin. A series of primary colorectal (90 cases) and primary pulmonary adenocarcinomas (86 cases) were also investigated. Four of 41 (10%) lung metastases of colorectal adenocarcinomas displayed a nuclear staining for TTF-1 with SPT24 clone. Three of the four positive cases displayed similar nuclear staining in primary and/or other extrathoracic metastatic sites as well as four of 90 (5%) primary colorectal adenocarcinomas, ruling out the role of lung microenvironment. None of them was positive with 8G7G1/1 clone. Sensitivity between two sets of antibodies was compared in 86 primary pulmonary adenocarcinomas. Nuclear staining was detected in 72 cases (84%) with Novocastra's antibody and 56 cases (65%) with Dako's. Significant discordance was observed (P < 0.01). These results suggest that the diagnostic virtue of TTF-1 detection depends on the used antibody's clone. The SPT24 clone seems to have a stronger affinity for TTF-1 protein but may lead to a few positive colorectal adenocarcinomas.

Lack of relationship between EGFR-1 immunohistochemical expression and prognosis in a multicentre clinical trial of 93 patients with advanced primary ovarian epithelial cancer (GINECO group)

Epidermal growth factor receptor 1 (EGFR-1) overexpression is usually described as linked with a worse prognosis in a variety of tumours of epithelial origin. However, its role in ovarian cancer is still controversial. The aim of the present study was to analyse the prognostic impact of EGFR-1 in a retrospective series of 93 stage III–IV primary ovarian epithelial tumours. All patients, enrolled in a multicentre GINECO prospective clinical trial, were treated with the same platinum-based combination chemotherapy, and were followed up with a median of 69 months. Epidermal growth factor receptor 1 plasma membrane expression, assessed by immunohistochemistry on paraffin-embedded tissues, was correlated with clinical parameters as well as immunohistochemical expression results of HER-2 (c-erbB-2), BAX, BCL-2, p53 and anti-Ki-67, previously studied in the same series of patients. Positive immunostaining for EGFR-1 was seen in 31 of the 93 analysed cases (33%). No correlation was found between EGFR-1 expression and clinical parameters. No correlation was found between EGFR-1 expression and other biological markers, except for HER-2, which was limit for significance. Indeed, among the EGFR-1-negative cases, 10.3% expressed HER-2, whereas the HER-2-expressing tumours accounted for 27.6% of EGFR-1-positive cases (P=0.06). Epidermal growth factor receptor 1 overexpression had no prognostic impact on both overall and progression-free survival through univariate and multivariate analyses. The potential effect of EGFR-1 and HER-2 co-expression on targeted therapy against EGFR-1 and/or HER-2 molecules has to be further analysed.

Peroperative frozen section analysis of TTF-1 antigen expression

BACKGROUND

The assessment of thyroid transcription factor 1 (TTF-1) expression is a useful way to investigate the origin of lung adenocarcinomas or large cell carcinomas when dealing with a solitary lung nodule in a patient with a history of extrathoracic cancer. However, if immunohistological analysis has not been performed before surgery, a peroperative frozen section may be insufficient to distinguish between a primary pulmonary tumour and a metastatic tumour.

AIMS

To develop a technique for the rapid assessment of TTF-1 expression that could improve the ability of frozen section peroperative histological diagnosis to answer such questions.

METHODS

A rapid immunohistochemical technique (lasting 30 minutes) to assess the expression of TTF-1 was developed and tested.

RESULTS

Among the 45 interpretable cases, results of frozen section immunohistochemistry were similar to those found by the standard immunohistochemical technique for the expression of TTF-1.

CONCLUSIONS

This technique enables TTF-1 to be analysed peroperatively, but further prospective studies are needed to assess its usefulness in routine practice.