Chromosomal deletions are the most frequent genetic alterations observed in hepatocellular carcinoma. Loss of heterozygosity on chromosome 4q has been observed in 40% of hepatocellular carcinomas suggesting the presence of a tumor suppressor gene which has not yet been identified.

The aim of this study was to compare 64 genetically determined pheochromocytomas (PH) (49 MEN IIa, 3 MEN IIb, 6 Von Recklinghausen diseases, 1 von Hippel-Lindau disease, 5 familial pheochromocytomas) and 48 sporadic PH. Genetically determined PH were more often observed among men and more frequently bilateral and multicentric than sporadic PH. Sporadic tumors had more often adrenal capsular invasion, necrosis and pseudocysts. Genetically determined PH were more differentiated with an insular pattern, hyaline globules and a higher percentage of polyhedric cells. Sporadic tumors were less differentiated with more frequently a diffuse pattern and small cells. Adrenal medullar hyperplasia was significantly associated with genetically determined PH. Adrenal cortical hyperplasia was not associated with a particular type of PH. The PS100 and chromogranin immunodetection was equivalent in both groups.

The frequency of leukemia and myelodysplasia following treatment with cytotoxic agents is increasing. Theses treatment-related leukemias raise both theoretical and practical concerns. On a theoretical basis, cytogenetic and molecular abnormalities described constitute useful models to study leukemogenesis. On a practical basis, prognosis of treatment related-leukemia is somehow unfavorable and implies to take in account this risk in the development of combination therapy for solid tumors or hematological malignancies. There are two distinctive types of treatment-induced leukemia: those secondary after alkylating agents and those secondary after topoisomerase-II- inhibitors. These two types of leukemia after regarding their clinical and their hematological characteristics, but also regarding their prognosis and their associated molecular abnormalities. Leukemias induced by alkylating agents occur generally 5 or 6 years after the beginning of the chemotherapy and are preceded by a more or less long phase of pancytopenia or myelodysplasia and according to their cytologic aspects are difficult to be classified within FAB classification. Their prognosis is pejorative. The most commonly found cytogenetic abnormalities associated with these types of induced leukemia are losses or deletions of chromosomes 5 and 7. Leukemias induced by topoisomerase-II-inhibitors occur shortly after the treatment (12 to 30 months), they begin generally suddenly without preleukemia prodom and their more frequent cytological aspects are M4 and M5 type. The prognosis is less severe than alkylating agent related forms with higher response rates and is dependant of discovered cytogenetic abnormalities. The more frequent molecular abnormalities are not chromosome deletions but balanced translocations. They affect particularly the MLL gene located at band 11q23. Other translocations have been described in this type of leukemia and are comparable to the one found in the de novo leukemia (t8;21, t15;17) for example. The evaluation of the risk of treatment-related leukemia for a given chemotherapeutic agent is difficult as for as current treatment use the combination of several agents potentially leukemogenic (chemotherapy and radiotherapy, combination chemotherapy). It is necessary to set up an up-dated data register in order to centralize all therapy-related myelodysplasia and leukemia within the treatment of a given type of cancer.

Uterine leiomyomata, or fibroids, represent the most common tumor in women of reproductive age. Although benign, leiomyomata constitute a major health problem, and are the most frequent indication for hysterectomy. The pathobiology of these tumors is still poorly understood. Cytogenetic and genetic studies have, in recent years, advanced our understanding of the etiology of these tumors. Specifically, cytogenetic aberrations involving chromosomes 6, 7, 12 and 14 have been shown to constitute the major chromosomal abnormalities seen in leiomyomata and have led to the discovery that HMGIC and HMGIY, two members of the non-histone high mobility group of genes, are involved in fibroid development. HMGIC and HMGIY map to 12q15 and 6p21, and their disruption or dysregulation has been shown to contribute to leiomyomata formation. Given the observation of several additional, but consistent, chromosomal aberrations, it is likely that other genes with fundamental roles in the pathobiology of uterine leiomyomata await identification. Furthermore, twin studies and the discovery of both ethnic and familial predispositions have suggested a genetic liability to develop uterine leiomyomata.

The identification of several types of familial colorectal cancer has led to the discovery of some of the genes involved in these diseases. It was subsequently shown that somatic mutations of these genes (APC, mismatch repair genes, TP53) also occur in sporadic colorectal cancer. Gradually, this molecular information is being incorporated into the standard histopathological analysis of colorectal cancer and can be used for the characterization of primary tumors. Although attempts have been made to use molecular parameters to better define dysplasia grades, differentiate between adenoma and carcinoma, and subtype carcinomas, histological parameters remain the standard for the classification of primary tumors. Nonetheless, molecular parameters may help define subgroups of colorectal carcinoma differing in prognosis and requiring individualized treatment regimens. Interesting possibilities are predicting the response of chemotherapy or radiotherapy at a molecular level and the search for metastasis by looking for molecular markers in lymph nodes or circulating blood. Other pathological tests being developed include the detection of K-ras, TP53 or APC mutations in stool and plasma. Such approaches will have a significant impact on the clinical management of colorectal cancer.