Prognostic value of circulating KRAS2 gene mutations in colorectal cancer with distant metastases.

While tissue KRAS2 mutations have been extensively investigated, the role of circulating mutant KRAS2 gene in patients with colorectal carcinoma remains obscure. The aim of the present study was to explore the prognostic significance of circulating KRAS2 gene mutational status in subjects undergoing primary treatment for colorectal cancer. Codon 12 KRAS2 mutations were examined in DNA samples extracted from the serum of 86 patients with colorectal cancer and were compared with the KRAS2 status of their primary tumors. Tissue and serum KRAS2 status was compared with other clinicopathological variables (including CEA and CA 19-9 levels) and with cancer-related survival. KRAS2 mutations were found in tissue samples of 28 patients (33%); serum KRAS2 mutations were detected in 10 of them (36%). Serum KRAS2 status was significantly associated with Dukes' stage D (p=0.001) and with preoperative CA 19-9 levels (p=0.01). At multivariate analysis, cancer-related survival was associated with Dukes' stage (p<0.0001), CEA level (p=0.02), and mutant circulating KRAS2 (p=0.01). All 7 stage D patients with serum KRAS2 mutations died of the disease within 24 months of primary treatment; cancer-related survival was significantly better in 9 stage D patients without serum KRAS2 mutations, with 5 patients (56%) alive after 24 months and 1 patient (13%) alive after 44 months. Residual disease after surgery was evident in all 7 stage D patients with mutant circulating KRAS2, and in 5 out of 9 stage D patients without serum mutations. Serum KRAS2 status may impact substantially on the management of stage D colorectal carcinoma, since it appears to cor-relate with prognosis in this patient subgroup.

Illegitimate villin transcripts in normal bone marrow precludes detection of colon cancer micrometastases.

Villin is a specific marker for normal and tumoral colon tissue. We have developed a highly sensitive assay using reverse transcription (RT) and real-time PCR to detect villin transcripts. The sensitivity of detection is one colon cancer cell. However, high levels of illegitimate villin transcripts were observed in normal bone marrow, precluding the use of villin RT-PCR for routine detection of colon cancer cells in bone marrow of patients with colon cancer.

Molecular detection of codon 12 K-RAS mutations in circulating DNA from serum of colorectal cancer patients.

Point mutations of the K-RAS gene at codon 12 are found in about 40% of cases with colorectal cancer. The diagnostic implications of the detection of these mutations and their clinical utility are still unclear. The aim of this study was to test both the feasibility of the detection of the mutated K-RAS gene in serum and its potential role in colorectal cancer detection and monitoring. Codon 12 K-RAS mutations were examined in DNA extracted from the serum of 35 patients with colorectal cancer and were compared with the K-RAS status in the corresponding primary tumor. Molecular detection was performed by the mutant-enriched PCR (ME-PCR) assay, a sensitive method capable of distinguishing a small quantity of mutated DNA in the presence of abundant wild-type DNA. The occurrence of mutations was compared with clinicopathological parameters as well as CEA and CA19.9 serum levels. We found codon 12 K-RAS mutations in the tissue of 13/35 (37%) patients. Serum mutations were detected in 5/13 (38.5%) patients with mutated K-RAS in the tissue. 26/35 (74%) patients showed an identical K-RAS pattern in tissue and serum. No codon 12 K-RAS alterations were found in serum samples of 22 patients with benign gastrointestinal diseases. Elevated serum CEA levels were detected in 16 patients, four of whom also presented serum RAS mutations. Our results confirm that K-RAS mutations can be found in circulating DNA extracted from serum samples of patients with colorectal cancer and show that there is a correspondence between serum and tissue K-RAS patterns.

Impact of steroid receptors, pS2 and cathepsin D on the outcome of N+ postmenopausal breast cancer patients treated with tamoxifen.

In spite of the complexity of the biological basis of the hormonal regulation of breast cancer, clinical studies tend to simplify the information by mainly categorizing continuous variables related to hormonal status and not considering the interactions between variables. The present study was planned to examine the presence of an interaction between cathepsin D (Cath-D) and pS2 in patients treated with adjuvant tamoxifen in a homogeneous subset of node-positive postmenopausal patients and to evaluate the contribution of the interaction to the predictive ability of the model. Steroid receptors (ER and PgR) were measured in cytosol using the dextran-coated charcoal method, while Cath-D and pS2 were determined using commercially available immunoradiometric assays. The prognostic role of each variable and their joint effect were investigated using a Cox regression model. Biological variables were analyzed as continuous and when their prognostic relationship did not seem linear, a restricted cubic spline regression smoothing approach was adopted. The logarithm of hazard showed a linear relationship with the log(ER), while it i) remained almost constant up to about 20 fmol/mg and subsequently decreased for PgR; ii) was almost constant up to about 50 pmol/mg and subsequently decreased for Cath-D; iii) decreased for increasing log(value) up to about 33 ng/mg and subsequently increased for pS2. In the multivariate analysis both PgR and the interaction between pS2 and Cath-D retained a significant prognostic role. For low values of pS2, the prognosis worsened with the increase in Cath-D levels and this relationship reversed for high values of pS2. From the results of the present study we can conclude that i) a significant interaction between Cath-D and pS2 was found in this case series; ii) the prognostic relationship should not be underestimated in clinical decision making; iii) a predictive score obtained considering the contribution of PgR, pS2 and Cath-D could be useful for clinical use.

ErbB2 assay in breast cancer: possibly improved clinical information using a quantitative method.

ErbB2/neu protein (p185) expression was evaluated by ELISA in 115 breast cancer specimens. Distribution was subdivided in quartiles and showed a distinct behaviour in comparison with both clinico-biological parameters and clinical outcome. In particular, intermediate concentration groups showed a significantly better disease-free survival than the low and high concentration groups (p = 0.02). We classified the patients as "low risk" (64 samples with p185 concentrations between 2150 and 30000 U/mg of proteins) and "high risk" on the basis of the results of the multivariate analysis. The p185 grouped as described showed a significant relationship with the disease free survival in multivariate analysis. Although the data must be considered as preliminary, they suggest the possibility of identifying more appropriately the high risk patients through the biochemical determination of p185.