TERT RNAscope analysis of sub-centimetric papillary thyroid carcinomas and synchronous lymph node metastases.

BACKGROUND: Sub-centrimetric papillary thyroid carcinomas usually have a good prognosis with a cancer specific survival of > 99%, however in up to 65% of patients, lymph node metastases can be observed. Molecular alterations in BRAF, TERT and TP53 are associated with worse clinicopathological outcome in patients with papillary thyroid carcinoma. MATERIAL AND METHODS: Twenty-two cases of papillary thyroid carcinomas measuring ≤ 1 cm with synchronous lymph node metastases were examined regarding morphological patterns and immunohistochemical status of p53, Ki-67, and BRAF V600E status. TERT RNA expression in lymph node metastases were evaluated by RNAScope®. RESULTS: Morphological patterns were heterogeneous in both primary tumors and lymph node metastases. Proliferation indices measured by Ki-67 were low. Both primary and lymph node metastases were wild type for p53 by immunohistochemical analysis. No lymph node metastasis showed TERT expression by RNAScope®. CONCLUSIONS: Our data indicate that TERT expression is not involved in the development early lymph node metastasis in patients with sub-centimetric PTC.

Expression of cell cycle regulators and frequency of TP53 mutations in high risk gastrointestinal stromal tumors prior to adjuvant imatinib treatment.

Despite of multitude investigations no reliable prognostic immunohistochemical biomarkers in GIST have been established so far with added value to predict the recurrence risk of high risk GIST besides mitotic count, primary location and size. In this study, we analyzed the prognostic relevance of eight cell cycle and apoptosis modulators and of TP53 mutations for prognosis in GIST with high risk of recurrence prior to adjuvant treatment with imatinib. In total, 400 patients with high risk for GIST recurrence were randomly assigned for adjuvant imatinib either for one or for three years following laparotomy. 320 primary tumor samples with available tumor tissue were immunohistochemically analyzed prior to treatment for the expression of cell cycle regulators and apoptosis modulators cyclin D1, p21, p16, CDK4, E2F1, MDM2, p53 and p-RB1. TP53 mutational analysis was possible in 245 cases. A high expression of CDK4 was observed in 32.8% of all cases and was associated with a favorable recurrence free survival (RFS), whereas high expression of MDM2 (12.2%) or p53 (35.3%) was associated with a shorter RFS. These results were independent from the primary KIT or PDGFRA mutation. In GISTs with higher mitotic counts was a significantly increased expression of cyclin D1, p53 and E2F1. The expression of p16 and E2F1 significantly correlated to a non-gastric localization. Furthermore, we observed a significant higher expression of p21 and E2F1 in KIT mutant GISTs compared to PDGFRA mutant and wt GISTs. The overall frequency of TP53 mutations was low (n = 8; 3.5%) and could not be predicted by the immunohistochemical expression of p53. In summary, mutation analysis in TP53 plays a minor role in the subgroup of high-risk GIST before adjuvant treatment with imatinib. Strong expression of MDM2 and p53 correlated with a shorter recurrence free survival, whereas a strong expression of CDK4 correlated to a better recurrence free survival.

Spatial expression of germ cell markers during maturation of human fetal male gonads: an immunohistochemical study.

BACKGROUND: The aim of the present study was to examine fetal male germ cells for expression of proteins associated with differentiation and maturation and to compare them with morphologically defined subpopulations. METHODS: Testes of 61 fetuses from week 12 of gestation to the newborn period were selected. Immunohistochemistry was performed using antibodies to proteins associated with differentiation of germ cells (c-KIT, AP-2gamma) or pluripotency (OCT3/4), oncofetal protein M2A and spermatogonial marker MAGE-A4. RESULTS: Two subtypes of fetal germ cells were detected by quantification and immunohistochemistry. Nearly all germ cells with morphological criteria of gonocytes and intermediate cells co-expressed OCT3/4, c-KIT, M2A and AP-2gamma. Starting from week 12, their number increased up to week 18/19 and then declined continuously during further development. After week 25, pre-spermatogonia were predominant and expressed MAGE-A4 selectively. CONCLUSIONS: Fetal male germ cells are comprised of two major groups with distinct immunohistochemical phenotypes. Germ cells that are predominantly found before week 25 of gestation co-express oncofetal proteins OCT3/4, c-KIT, M2A and AP-2gamma. After week 25, most germ cells have lost their pluripotent potential and acquire a spermatogonial phenotype defined by expression of MAGE-A4.