Formalin-fixed paraffin-embedded (FFPE) tissue blocks are widely used to identify clinically actionable molecular alterations or perform retrospective molecular studies. Our goal was to quantify degradation of DNA occurring during mid to long-term storage of samples in usual conditions. We selected 46 FFPE samples of surgically resected carcinomas of lung, colon, and urothelial tract, of which DNA had been previously extracted. We performed a second DNA extraction on the same blocks under identical conditions after a median period of storage of 5.5 years. Quantitation of DNA by fluorimetry showed a 53% decrease in DNA quantity after storage. Quantitative PCR (qPCR) targeting KRAS exon 2 showed delayed amplification of DNA extracted after storage in all samples but one. The qPCR/fluorimetry quantification ratio decreased from 56 to 15% after storage (p < 0.001). Overall, remaining proportion of DNA analyzable by qPCR represented only 11% of the amount obtained at first extraction. Maximal length of amplifiable DNA fragments assessed with a multiplex PCR was reduced in DNA extracted from stored tissue, indicating that DNA fragmentation had increased in the paraffin blocks during storage. Next-generation sequencing was performed on 12 samples and showed a mean 3.3-fold decrease in library yield and a mean 4.5-fold increase in the number of single-nucleotide variants detected after storage. In conclusion, we observed significant degradation of DNA extracted from the same FFPE block after 4 to 6 years of storage. Better preservation strategies should be considered for storage of FFPE biopsy specimens.

The specific SMARCB1/INI1 inactivation observed in RMCs suggests that RMC and CDC are different entities.

Pathological assessment of bladder cancer is becoming an increasingly complex task owing to the growing availability of molecular data for different histological subtypes and the appreciation of their importance in determining outcomes of neoadjuvant chemotherapy. Urologists are aware of the need to closely collaborate with pathologists, and comprehensive sharing of information is crucial to achieve optimal patient management. Numerous steps towards this goal have been made during the past years. Important advances in the assessment and reporting of grading and staging, especially substaging of pT1 urothelial carcinomas, have been made. As part of the International Collaboration on Cancer Reporting (ICCR), an international expert group has suggested worldwide reporting standards for urothelial lesions. Nevertheless, several issues remain unresolved, for example, regarding the reporting of heterogeneous lesions and substaging as well as the gross handling and the reporting for lymphadenectomy specimens. During the past few years, major insights have been gained into the molecular changes that occur during bladder cancer development, but a consensus on how to integrate these data into daily practice has not been achieved.

Epstein-Barr virus (EBV)-infected B cells with Reed-Sternberg-like cell (RS) features may occur in peripheral T-cell lymphomas (PTCLs), especially in angioimmunoblastic T-cell lymphoma. Here, we report 5 patients presenting with lymphadenopathy whose first biopsies demonstrated nodular lymphoid proliferations containing scattered CD30+, CD15+, EBV+ Hodgkin and Reed-Sternberg-like cells, which led to an initial diagnosis of lymphocyte-rich classical Hodgkin lymphoma. However, the uncommon clinical features and/or the occurrence of relapse as PTCL prompted review of the biopsies with expanded immunohistologic and molecular studies and revision of the diagnoses to follicular variant of PTCL (F-PTCL). All cases had atypical small to medium-sized CD3+ T cells that expressed CD10 (4/5) and the follicular helper T-cell (TFH) antigens BCL6, PD1, CXCL13, and ICOS. All demonstrated clonal T cells with a similar pattern in multiple samples from 4 patients. In 2 cases, flow cytometry demonstrated circulating lymphocytes with an abnormal sCD3+, CD4+, ICOS+ immunophenotype. Two patients had a skin rash at presentation, and 1 had B symptoms. Two of the 4 patients treated with polychemotherapy are alive at 3 and 6 years after first diagnosis. These cases highlight how some F-PTCLs may closely mimic lymphocyte-rich classical Hodgkin lymphoma requiring careful assessment of the T cells before rendering the latter diagnosis. The functional properties of TFH cells might lead to the presence of EBV-positive B blasts with RS-like features in TFH-derived PTCL such as angioimmunoblastic T-cell lymphoma and F-PTCL.