As part of a clinical research project, proliferative parameters were studied in primary breast cancer: standardization and technical validation of thymidine kinase (TK), thymidylate synthase (TS) and protein tyrosine kinase (PTK) are described. A total of 633 frozen tumor specimens, available in four institutions, was analyzed in three flow cytometry laboratories for DNA content and percentage of S-phase cells (%S) measurement. 1) The standardization step consisted in developing a common protocol for sample preparation; then, common cell suspensions were analyzed in order to perform an inter-laboratory control. Objective guidelines were elaborated to interpret DNA histograms in breast carcinoma. 2) DNA-aneuploidy was observed in 61% of cases of the retrospective series. Compared with DNA-aneuploid tumors, mean %S was significantly lower in case of DNA-diploidy (respectively: 6.4% and 2.2%, p < 0.001). When compared between the four institutions, %S distributions did not differ significantly. 3) %S is strongly correlated with TK, TS and PTK and high percentages were also observed in high grade tumors or tumor without hormone receptors. These results show that a standardization in using flow cytometers and DNA software allows multicenter studies.

Prostate cancer is an androgen-dependent tumor which presents an androgen-independent regrowth after clinical regression in response to antiandrogen treatment. Four hypotheses have been developed to understand how androgen signal transduction pathway mediate androgen-independent tumor progression: over expression of the wild-type androgen-receptor gene, androgen-receptor gene mutation, excessive recruitment of transcriptional co-activator ARA-70 and a cross-talk between the androgen-receptor and the growth factor receptor pathways. In this work, C. Sawyers's group elegantly demonstrates, in LAPC-4 androgen-independent prostate cancer sublines, that forced hyperexpression of HER-2/Neu receptor tyrosine kinase allowed androgen-independent growth, that HER-2/Neu activated the androgen-receptor pathway in the absence of androgens and synergized with low levels of androgen to superactivate the pathway. These important data could have therapeutic implications for the management of androgen-independent prostate cancer.

Langerhans cell histiocytosis is an uncommon clonal disorder. Its reactional or genetic nature is debated.

Medullary thyroid carcinoma is a rare disease which originates from the secretion of calcitonin by thyroid parafollicular cells. Sporadic (75%) and inherited (25%) forms of the disease are encountered. Familial forms (termed multiple endocrine neoplasia type IIa, IIb, or familial medullary thyroid carcinoma) may or may not be associated with other endocrinopathies such as pheochromocytoma and/or hyperparathyroidism.

HER2 is overexpressed in about 25% to 30% of breast cancers and associated with poor prognosis, resistance to hormonotherapy and lack of sensitivity to CMF-based adjuvant chemotherapy. Herceptin (trastuzumab), a humanized monoclonal antibody, administered as a single agent, produces objective responses in phase II trials in patients with metastatic breast cancers overexpressing HER2. It has shown a substantial benefit in a phase III trial which compares a standard first line chemotherapy (doxorubicin and cyclophosphamide or taxol alone) to the same chemotherapy with Herceptin in metastatic breast cancer. The Herceptin arm had significantly higher response rate (+ 53%), an improvement in the median duration of response (+ 57%) as well as in time to progression (+ 65%) compared to chemotherapy alone.

The authors report a child male case of secretory carcinoma of the breast, associated with a abnormal tumoral karyotype (monosomy 22). The diagnosis was made by histopathological examination. This breast carcinoma is characterized by an abundant intra and extracellulary secretory material, which present a reactivity with antimilk proteins antibodies and includes spherical dense bodies, identified by ultrastructural study. The prognosis is not bad, whatever the age of the patient, particularly for the children and young women, displaying an locoregional aggressivity. The signification of a monosomy 22 in secretory carcinoma is unknown.

The study of epidemiology and of the carcinogenesis in epidermoid carcinomas of the upper aerodigestive tract shows that their occurrence is not random. Tobacco abuse plays a major role, especially because of benzopyrene, mutagen of the P53 gene, however it is associated with many other potentiating factors: alcohol, metals, hydrocarbures, virus, food, climate, genetic fragility that create genetic lesions at the origin of carcinogenesis. The latter occurs as "field cancerization" with multiple alterations of the mucosa and general attack of the control systems of the differentiation, growth and cell apoptosis which usually protect the cell against the phenomena of carcinogenesis. The P53 protein gene, retinoid receptors as well as the system of detoxifying glutathion S transferase are modified at the very early stage of these diseases, these abnormalities can be logically related to epidemiological data. These data lead us therefore to imagine complementary specific reverting therapies of induced genetic abnormalities, through the reexpression of non mutated gene encoding P53 protein and the use of retinoid. These various modalities are reported hereafter.

We report on Gorlin-Goltz syndrome observed in 4 patients belonging to three generations of the same family. We present the clinical findings and emphasize recent genetic discoveries. We discuss the difficulty in following these patients and propose a series of simple explorations which can be helpful.

A new type of mutation by deletion-insertion in BRCA-1 gene is found in three unrelated French breast/ovarian cancer families. Surprisingly, deletion and insertion occurred at the same nucleotide position at the end of exon 11 (3958del5ins4), thus generating a truncated protein. This original mutation consists in a deletion of 5 bp (CTCAG) and in an insertion of 4 different bp (AGGC). Here, we proposed two hypothesis to explain this phenomenom. The first hypothesis is the formation of a hairpin stem-loop structure comprising the mutational site and the sequence corresponding to the duplication insertion 2 nucleotides before the mutation. The second hypothesis, more speculative, consists in an abortive integration of a human mobile element as a human transposon (tigger 1) which involved a deletion of 5 bp during its excision and an insertion of 4 bases corresponding to the 5' extremity of the transposon.

Tumours arising from the thyroid follicular cell have proven to be a very useful model for studying the molecular genetics of tumour development. This review summarises our current knowledge of the principal abnormalities of oncogenes and tumour suppressor genes associated with the major sub-types of thyroid tumour. The pattern which emerges demonstrates well how successive genetic abnormalities drive clonal progression. In addition, comparison of follicular and papillary sub-types provides a fascinating example of how the nature of the underlying genetic abnormality may determine the clinico-pathological behaviour of the resulting tumour. The potential impact of this molecular data on clinical management is also discussed.

Familial adenomatous polyposis (FAP) is an inherited autosomal dominant disorder with marked propensity for malignant transformation. The potential for congenital hypertrophy of retinal pigment epithelium (CHRPE) as a phenotypic marker for this disease is recognized.

Recent studies have demonstrated the close link between oncogenesis and cell cycle machinery. Cyclin dependent kinase inhibitory proteins (Ckis) have been shown to be implicated in cancer progression. We investigated the levels of the different regulatory inhibitory proteins involved in the G1 progression and G1/S in choroidal melanomas.