Evaluation of HER2 expression in urothelial carcinoma cells as a biomarker for circulating tumor cells

Background Detection of circulating tumor cells (CTC) by techniques based on epithelial cell adhesion molecule (EpCAM) is suboptimal in urothelial carcinoma (UC). As HER2 is thought to be broadly expressed in UC, we explored its utility for CTC detection. Methods HER2 and EpCAM expression was analyzed in 18 UC cell lines (UCCs) by qRT-PCR, western blot and fluorescence-activated cell scanning (FACS) and compared to the strongly HER2-expressing breast cancer cell line SKBR3 and other controls. HER2 expression in UC patient tissues was measured by qRT PCR and correlated with data on survival and risk for metastasis. UCCs with high EpCAM and variable HER2 expression were used for spike-in experiments in the CellSearch system. Twenty-one blood samples from 13 metastatic UC patients were analyzed for HER2-positive CTCs with CellSearch. Results HER2 mRNA and protein were broadly expressed in UCC, with some heterogeneity, but at least 10-fold lower than in the HER-2+ SKBR3 cells. Variations were unrelated to cellular phenotype or clinicopathological characteristics. EpCAM expression was essentially restricted to UCCs with epitheloid phenotypes. Heterogeneity of EpCAM and HER2 expression was observed also in spike-in experiments. The 7 of 21 blood samples from 6 of 13 patients were enumerated as CTC positive via EpCAM, but only one sample stained weakly positive (1+) for HER2. Conclusions Detection rate of CTCs by EpCAM in UC is poor, even in metastatic patients. Because of its widespread expression, particularly in patients with high risk of metastasis, detection of HER2 could improve identification of UC CTCs, which is why combined detection using antibodies for EpCAM and HER2 may be beneficial

Late relapsing germ cell tumors with elevated tumor markers

Purpose!#!Late relapsing germ cell tumors (LR-GCT) are considered a rare distinct biologic entity as their clinical presentation and response to treatment is different to early recurrences. While serum tumor markers (AFP and ß-HCG) play an important role at the time of first diagnosis to correctly classify prognosis and treatment of germ cell tumors, they may not have the same significance in a late relapse situation.!##!Patients and methods!#!Thirty-seven patients with LR-GCT with elevated serum tumor markers were identified in our database. Twenty-six patients underwent primary surgical resection of the late relapsing tumor. Eleven patients received salvage chemotherapy and a post-chemotherapy residual tumor resection. Serum tumor markers, histological findings and oncological outcome were analyzed.!##!Results!#!In the histopathological specimen, viable cancer was found in 20 cases (54%) and teratoma was found in 16 cases (43%). In nine cases (24%), a somatic-type malignant transformation was present. In 19 of 37 patients (51.4%), the late relapse specimen presented a histological type of GCT, which was not present in the primary histology. Twenty-two patients (59.5%) were included in follow-up analysis. Mean and median follow-up time was 62.2 and 53 months, respectively. Seventeen patients (77.3%) suffered a relapse or had progressive disease after LR therapy. Five patients (22.7%) have been relapse-free after LR therapy (mean FU 61.6 months). Ten patients died of disease during follow-up (45.5%) and had a mean time from LR to death of 66.4 months. Eleven patients were alive at last follow-up (mean FU 62.2 months). Relapse and survival rate were similar between patients who received primary resection of LR tumor and patients who received salvage chemotherapy followed by surgery.!##!Conclusion!#!Patients with a late relapsing germ cell tumor and elevated markers have a poor prognosis and a high risk for another relapse independent on primary treatment. The histological type and aggressiveness of a late relapsing tumor cannot be predicted with serum tumor marker levels at the time of diagnosis of LR. In up to 54% of cases, primary histology did not coincide with LR histology. Therefore, we propose primary surgical resection of a late relapsing tumor if a complete resection is feasible in order to gain exact histology and tailor further treatment