β2microglobulin mRNA expression levels are prognostic for lymph node metastasis in colorectal cancer patients

Colorectal cancer (CRC) is the fourth most common non-cutaneous malignancy in the United States and the second most frequent cause of cancer-related death. One of the most important determinants of CRC survival is lymph node metastasis. To determine whether molecular markers might be prognostic for lymph node metastases, we measured by quantitative real-time RT–PCR the expression levels of 15 cancer-associated genes in formalin-fixed paraffin-embedded primary tissues derived from stage I–IV CRC patients with (n=20) and without (n=18) nodal metastases. Using the mean of the 15 genes as an internal reference control, we observed that low expression of β2microglobulin (B2M) was a strong prognostic indicator of lymph node metastases (area under the curve (AUC)=0.85; 95% confidence interval (CI)=0.69–0.94). We also observed that the expression ratio of B2M/Spint2 had the highest prognostic accuracy (AUC=0.87; 95% CI=0.71–0.96) of all potential two-gene combinations. Expression values of Spint2 correlated with the mean of the entire gene set at an R2 value of 0.97, providing evidence that Spint2 serves not as an independent prognostic gene, but rather as a reliable reference control gene. These studies are the first to demonstrate a prognostic role of B2M at the mRNA level and suggest that low B2M expression levels might be useful for identifying patients with lymph node metastasis and/or poor survival

Immunohistochemical detection of E-cadherin, α- and β-catenins in papillary thyroid carcinoma

E-cadherin and catenins play a major role in neoplastic cell behavior as a suppressor of invasion and/or metastasis. The aim of this study was to determine E-cadherin, alpha-catenin and beta-catenin expressions in papillary thyroid carcinoma (PTC) and to correlate the results of expression to initial clinicopathological parameters and clinical outcome. Forty-one cases (mean age 37.3 +/- 11.2 yr) with PTC were studied. Patients were followed-up with a mean period of 47.6 +/- 27.0 months. A retrospective immunohistochemical analysis of E-cadherin, alpha-catenin and beta-catenin was performed on paraffin-embedded tissue sections. Tissues from ten patients with benign goiter were used as controls. E-cadherin, alpha- and beta-catenin immunoreactivities were found in 80% (33/41), 76% (31/41) and 97% (40/41) of patients respectively. No correlation was found between E-cadherin, alpha- and beta-catenin immunoreactivities and sex, local invasion or lymphatic spread at the time of initial examination. Distant metastases and/or local recurrences developed in 6 patients during follow-up. Recurrences/metastases developed both E-cadherin, alpha- and beta-catenin positive and negative primary tumors. Disease-free survival curves according to Kaplan-Meier analysis and log-rank test did not show any significant differences between E-cadherin, alpha- and beta-catenin positive and negative patients. According to our findings, E-cadherin, alpha- and beta-catenin expressions may not add any valuable information to the follow-up in a subgroup of PTC patients with a relatively benign course. (C) 2002, Editrice Kurtis