Aims
Malignant germ cell tumours (GCTs) of the testis are rare neoplasms, but the most common solid malignancies in young men. World Health Organization guidelines divide GCTs into five types, for which numerous immunohistochemical markers allow exact histological subtyping in the majority of cases. In contrast, a germ cell origin is often hard to prove in metastatic GCTs that have developed so‐called somatic malignant transformation. A high percentage, up to 89%, of GCTs are characterised by the appearance of isochromosome 12p [i(12p)]. Fluorescence in‐situ hybridisation has been the most common diagnostic method for the detection of i(12p) so far, but has the disadvantages of being time‐consuming, demanding, and not being a stand‐alone method. The aim of the present study was to establish a quantitative real‐time polymerase chain reaction assay as an independent method for detecting i(12p) and regional amplifications of the short arm of chromosome 12 by using DNA extracted from formalin‐fixed paraffin‐embedded tissue.
Methods and results
A cut‐off value to distinguish between the presence and absence of i(12p) was established in a control set consisting of 36 tumour‐free samples. In a training set of 149 GCT samples, i(12p) was detectable in 133 tumours (89%), but not in 16 tumours (11%). In a test set containing 27 primary and metastatic GCTs, all 16 tumours with metastatic spread and/or somatic malignant transformation were successfully identified by the detection of i(12p).
Conclusion
In summary, the qPCR assay presented here can help to identify, further characterise and assign a large proportion of histologically inconclusive malignancies to a GCT origin.
Testicular germ cell cancer (TGCC) is the most common type of cancer in young men. Seminomas account for around half of them and are characterized by a pronounced infiltration of immune cells. So far, the impact of the tumor microenvironment (TME) on disease progression, especially the interaction of individual immune cell subtypes with the tumor cells, remains unclear. To address this question, we used an in vitro TME model involving the seminoma-derived cell line Tcam-2 and immune cell subsets purified from human peripheral blood. T cells and monocytes were strongly activated when individually cocultured with Tcam-2 cells as revealed by increased expression of activation markers and pro-inflammatory cytokines both on the mRNA and protein level. Importantly, the interaction between tumor and immune cells was mutual. Gene expression of pluripotency markers as well as markers of proliferation and cell cycle activity were upregulated in Tcam-2 cells in cocultures with T cells, whereas gene expression of SOX17, a marker for seminomas, was unaltered. Interestingly, the impact of monocytes on gene expression of Tcam-2 cells was less pronounced, indicating that the effects of individual immune cell subsets on tumor cells in the TME are highly specific. Collectively, our data indicate that seminoma cells induce immune cell activation and thereby generate a strong pro-inflammatory milieu, whereas T cells conversely increase the proliferation, metastatic potential, and stemness of tumor cells. Although the employed model does not fully mimic the physiological situation found in TGCC in vivo, it provides new insights potentially explaining the connection between inflammatory infiltrates in seminomas and their tendency to burn out and metastasize.
Purpose
The prognostic significance of lactate dehydrogenase (LDH) in patients with metastatic seminoma is not defined. We investigated the prognostic impact of LDH levels prior to first-line systemic treatment and other clinical characteristics in this subset of patients.
Methods
Files from two registry studies and one single-institution database were analyzed retrospectively. Uni- and multivariate analyses were conducted to identify patient characteristics associated with recurrence free survival (RFS), overall survival (OS), and complete response rate (CRR).
Results
The dataset included 351 metastatic seminoma patients with a median follow-up of 5.36 years. Five-year RFS, OS and CRR were 82%, 89% and 52%, respectively. Explorative analysis revealed a cut-off LDH level of < 2.5 upper limit of normal (ULN) (n = 228) vs. ≥ 2.5 ULN (n = 123) to be associated with a significant difference concerning OS associated with 5-years OS rates of 93% vs. 83% (p = 0.001) which was confirmed in multivariate analysis (HR 2.87; p = 0.004). Furthermore, the cut-off LDH < 2.5 ULN vs. ≥ 2.5 ULN correlated with RFS and CRR associated with a 5-years RFS rate and CRR of 76% vs. 86% (p = 0.012) and 32% vs. 59% (p ≤ 0.001), respectively.
Conclusions
LDH levels correlate with treatment response and survival in metastatic seminoma patients and should be considered for their prognostic stratification.
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