X-chromosome inactivation analysis of isolated Reed-Sternberg cells in nodular sclerosing Hodgkin's disease

Identification of prognostic factors in classic Hodgkin lymphoma by integrating whole slide imaging and next generation sequencing

Digital pathology and genomics are increasingly used to improve our understanding of lymphoid neoplasms. Algorithms for quantifying cell populations in the lymph node and genetics can be integrated to identify new biomarkers with prognostic impact in classic Hodgkin lymphoma (cHL). In 16 cHL patients, we have performed whole slide imaging (WSI) analysis and quantification of CD30+, CD20+, CD3+ and MUM1+ cells in whole tissue slides, and Next Generation Sequencing (NGS) in formalin fixed paraffin-embedded (FFPE) tissue, using a widely used NSG panel (Oncomine® Focus Assay) to define genetic variants underlying tumor development. The different cell populations could be successfully identified in scanned slides of cHL, supporting the inclusion of WSI in the histopathological evaluation of cHL as an adequate method for the quantification of different cell populations. We also performed genetic profiling in FFPE samples of cHL leading to the identification of copy number variations in the Neurofibromin 1 gene (17q11.2) and the Androgen Receptor gene (Xq12) accompanied by chromosomal gains and losses in CDK4, KRAS and FGFR2 genes. Progression-free survival (PFS) was statistically significantly higher in cHL patients with amplification in the NF1 gene combined with CD3+ cells above 28.6% (p = 0.006) and MUM1+ cells above 21.8% (p < 0.001). Moreover, patients with MUM1+ cells above 21.8% showed a statistically significantly higher PFS when combined with amplification of the AR gene (p < 0.001) and wild-type KRAS (p < 0.001). The integration of WSI analysis and DNA sequencing could be useful to improve our understanding of the biology of cHL and define risk subgroups.

Epstein-Barr-Virus-Infected CD15 (Lewis X)-Positive Hodgkin-Lymphoma-Like B Cells in Patients with Rheumatoid Arthritis

Patients with rheumatoid arthritis (RA), especially those who are treated with methotrexate (MTX), might have an increased risk of Hodgkin lymphoma (HL), a malignancy that is associated with Epstein-Barr virus (EBV). Here we describe a monoclonal EBV-infected B-lymphoblastoid cell line (LCL) called TKS-1 that was established from cells that spontaneously converted from an MTX-treated RA patient. TKS-1 has properties similar to HL cells and it is distinctly different from control LCLs established from normal individuals. TKS-1 cells express the HL -associated surface markers CD15 and CD30 (Takei et al. 1989). Like Hodgkin Reed-Sternberg (H-RS) cells of EBV-positive HL, TKS-1 cells express EBNA1 mRNA transcribed from the Qp promoter of the virus, whereas control LCLs use the Cp or Wp promoter to transcribe mRNA. TKS-1 cells can proliferate in an anchorage-independent manner and possess a cloning efficiency comparable to that of the Burkitt lymphoma (BL) line Raji. In addition, two EBV-positive LCLs established by cocultivated CD34+ cells isolated from the bone marrow of patients with RA and peripheral blood B lymphocytes from a healthy EBV-seronegative individual also expressed CD15. These results indicate that EBV-infected B-lymphoblastoid cells from patients with RA tend to acquire properties similar to HL cells.

Loss of E-cadherin expression resulting from promoter hypermethylation in oral tongue carcinoma and its prognostic significance

BACKGROUND

E-cadherin is expressed on the surface of normal epithelial cells. Loss of E-cadherin expression has been found in cancers and is postulated to facilitate tumor cell dissociation and metastasis. This study evaluated the role of promoter dense methylation in the downregulation of E-cadherin expression in oral tongue carcinoma.

METHODS

E-cadherin expression of 109 oral tongue carcinomas (93 primary tumors, 7 locally recurrent tumors, and 9 metastatic lymph nodes) was evaluated by immunohistochemical staining of tumor tissues. The methylation status of the CpG islands at the promoter region of E-cadherin which flanked five HpaII (methylation sensitive restriction enzyme) digestion sites were evaluated by methylation sensitive polymerase chain reaction in 86 tumors (70 primary tumors, 7 locally recurrent tumors, and 9 metastatic lymph nodes).

RESULTS

Underexpression of E-cadherin was found in 83% of primary tumors, 86% of recurrent tumors, and 89% of nodal metastases. Hypermethylated E-cadherin promoter was found in 64% of primary tumors, 71% of recurrent tumors, and 67% of nodal metastases. Downregulation of E-cadherin expression was found to be related to promoter hypermethylation. Consistently weak expression of E-cadherin by promoter hypermethylation was observed in primary tumors, their corresponding metastatic lymph nodes, and recurrent tumors. Downregulation of E-cadherin expression was a significant poor prognostic factor for survival.

CONCLUSIONS

Methylation of CpG sites at the promoter region played a key role in the inhibition of E-cadherin expression in both primary oral tongue carcinomas and their corresponding recurrences and nodal metastases. The resulting downregulation of E-cadherin expression had adverse effects on the prognosis of patients who were treated by primary surgery.