Energy allocation strategy of skipjack tuna Katsuwonus pelamis during their reproductive cycle

The lipid composition of somatic and reproductive tissues was determined for female skipjack tuna Katsuwonus pelamis caught in the western Indian Ocean between latitude 10° N and 20° S and longitude 40° and 70° E. The highest total lipid (TL) contents were in the liver and gonads, with white muscle levels approximately three-fold lower. Three lipid classes dominated: triacylglycerols (TAG), sterol esters and wax esters (SE-WE) and phospholipids (PL). Collectively, these accounted for between 70 and 80% of TLs. Changes in lipid concentrations were evaluated over the maturation cycle. Immature fish had the lowest gonad and liver TL levels; concentrations of TL, TAG, SE-WE and PL accumulated from immature to mature (spawning-capable) phase, reflecting sustained vitellogenic activity of the liver and a transfer of lipids to developing oocytes from the onset of vitellogenesis. Gonado-somatic and hepato-somatic indices were positively correlated with each other and positively related to TL in the gonads and liver. Fulton's condition index and lipid concentrations in muscle did not vary significantly over the maturation cycle; fat content in the main storage tissues was undepleted as the ovary developed. Hence, K. pelamis apparently supports reproduction directly from food intake over the breeding season. In the gonads, reserve lipids (SE-WE and TAG) and sterols were related to batch fecundity but this was not the case for somatic and hepatic tissues. These results suggest that K. pelamis utilizes an income breeding strategy.

Molecular characterization of small peripheral lung tumors based on the analysis of fine needle aspirates

The computed tomography (CT)-based early lung cancer diagnostic technologies allow the detection of very small stage I lung tumors. As part of these screening protocols any suspicious nodule has to be diagnosed morphologically, which requires CT-guided Fine Needle Aspiration, open biopsy or surgery. Fine Needle Aspiration (FNA) cytology is a well-recognised method for a rapid and accurate diagnosis of small lung tumors. Molecular analysis of the FNA specimens could complement cytology diagnosis by the characterization of the biological traits at the preoperative stage. In this study, we aimed to characterize the biological profile of 33 paraffin-embedded transthoracic FNA samples obtained from three groups of lung cancer patients: two groups of small early-detected lung adenocarcinomas (radiologically subsolid and solid nodules) and a third group of small metastatic adenocarcinomas. Genetic analysis was performed by fluorescence in situ hybridization using the four-color LAVysion probe. p53 and Ki-67 protein expression was also evaluated by immunocytochemistry. The samples showed gains for all targets analyzed; two cases had EGFR gene amplification and two cases had MYC amplification. There were no significant differences in the percentage of genetically malignant cells and the expression of Ki-67 among the three groups. However, p53 accumulation was significantly higher in the metastatic group compared to the subsolid early-detected group (P = 0.001). In conclusion, molecular analysis of FNA specimens may provide useful information at preoperative stages. In our series, a good prognostic profile in subsolid early detected adenocarcinomas is suggested.

[FICTION as a new tool to early lung cancer diagnosis]

Lung cancer is one of the most frequent causes of cancer death in Western countries. Overall 5-year survival rate is lower than 15% mainly due to the late diagnosis of the disease. Primary prevention (reduction of tobacco consumption) and more effective methods for early detection are needed. Some studies have recently shown that low-dose spiral computed tomography (CT) is a useful technique to the detection of pulmonary malignant nodules in early stages. Studies are developing to evaluate its efficacy in series of high-risk patients. A new cytogenetic technique has been developed: the FICTION technique (Fluorescence Immunophenotyping and Interphase Cytogenetics as a Tool for the Investigation of Neoplasms). This technique allows the simultaneous study of immunophenotypic markers and genetic abnormalities present in tumour cells. The goal of our project is optimise this technique in sputum and bronchoalveolar lavage specimens from lung cancer patients. The overall goal of this project is evaluate the usefulness of this technique, together with the new radiological techniques, in early detection programs of lung cancer in high-risk patients. In the present study we review the cytogenetic studies on lung cancer carried out in the recent years. We also introduce the basic methodological aspects that will be developed in our project.

Genomic imbalances detected by comparative genomic hybridization are prognostic markers in invasive ductal breast carcinomas

AIMS

The aim of this work is the study of the prognostic significance of the chromosomal aberrations described in a series of invasive ductal breast carcinomas.

METHODS AND RESULTS

We analysed by comparative genomic hybridization a group of 70 formalin-fixed paraffin-embedded invasive ductal breast carcinomas. Aberrations showed a frequency similar to previous studies using frozen tumours. Interestingly, we identified gains involving 6q16-q24 more frequently than in other series. We analysed the association among the chromosomal imbalances, 11 histopathological factors, relapse rate and overall survival of patients. Associations showed 16q losses as a potential marker of good prognosis, as they were more frequent in node-negative (P=0.025) and in oestrogen-positive tumours (P < 0.001). Furthermore, 100% of bcl-2+ tumours presented this aberration compared with 29.3% in bcl-2- (P=0.014). 1q, 11q, 17q and 20q gains were associated with poor prognosis: 95% of cases with 1q gains were bigger than 20 mm (P=0.041). Tumours with 1q and 11q gains showed a higher relapse rate (P=0.063; P=0.066). Within the good prognosis group of lymph node-negative patients, 17q and 20q gains identify a subgroup with increased relapse rate (P=0.039).

CONCLUSIONS

Chromosomal imbalances, together with histopathological factors, may help to predict outcome in breast cancer patients.

Comparative genomic hybridization and amplotyping by arbitrarily primed PCR in stage A B-CLL

Cytogenetic analysis is useful in the diagnosis and to assess prognosis of B-cell chronic lymphocytic leukemia (B-CLL). However, successful cytogenetics by standard techniques has been hindered by the low in vitro mitotic activity of the malignant B-cell population. Fluorescence in situ hybridization (FISH) has become a useful tool, but it does not provide an overall view of the aberrations. To overcome this hurdle, two DNA-based techniques have been tested in the present study: comparative genomic hybridization (CGH) and amplotyping by arbitrarily primed PCR (AP-PCR). Comparative genomic hybridization resolution depends upon the 400-bands of the human standard karyotype. AP-PCR allows detection of allelic losses and gains in tumor cells by PCR fingerprinting, thus its resolution is at the molecular level. Both techniques were performed in 23 patients with stage A B-CLL at diagnosis. The results were compared with FISH. The sensitivity of AP-PCR was greater than CGH (62% vs. 43%). The use of CGH combined with AP-PCR allowed to detect genetic abnormalities in 79% (15/19) of patients in whom G-banding was not informative, providing a global view of the aberrations in a sole experiment. This study shows that combining these two methods with FISH, makes possible a more precise genetic characterization of patients with B-CLL.