No Evidence for Viral Sequences in Mycosis Fungoides and Sézary Syndrome Skin Lesions: A High-Throughput Sequencing Approach

Black cat in a dark room: the absence of a directly oncogenic virus does not eliminate the role of an infectious agent in cutaneous T-cell lymphoma pathogenesis

“…Because directly carcinogenic viruses actively express oncogenes in tumour cells, sequencing a tumour transcriptome to a sufficient depth should detect viral transcript if present. Together with other SS studies, we can conclude that the possibility of MF or SS being caused by a directly oncogenic virus is exceedingly low, but – owing to some limitations of DTS, such as failure to detect a novel virus lacking homology to known species – not zero. Additionally, viral sequences erroneously characterized as human, such as the endogenous retroviruses, which comprise ~ 10% of the human genome, could be falsely subtracted during DTS.…”

“…Presently, none of the recent studies looking for evidence of HTLV‐1 in CTCL were able to identify this sequence . Because studies utilizing digital transcriptome subtraction techniques did not detect clonally integrated HTLV‐1 into the host genome, we can conclude with a high degree of certainty that HTLV‐1 is not a directly oncogenic virus in CTCL pathogenesis. However, it does not exclude a possibility that concurrent infection with HTLV‐1 could contribute to a chronic antigen stimulation model, which has long been proffered …”

“…CTCL specimens have been evaluated for evidence of infection, including by Staphylococcus aureus and members of the retrovirus, herpesvirus and polyomavirus families. However, studies have largely failed to reveal associations between infectious agents and CTCLs …”

Expression of Human Endogenous Retrovirus-W Including Syncytin-1 in Cutaneous T-Cell Lymphoma

“…Since MF, the most common form of CTCL, clinically resembles the smoldering form of adult T-cell lymphoma/leukemia, caused by human T-cell leukaemia/lymphoma virus I (HTLV-I) and since CTCL patients also have antibodies cross-reacting with HTLV-I and/or human immunodeficiency virus type 1 (HIV-1) core proteins [15,16] exogenous retroviruses were extensively sought for as an etiologic agent. However, neither replicating retroviruses nor any other viruses have been found in CTCL [17-22]. …”

No evidence for viral transcripts in dermatofibrosarcoma protuberans

“…High molecular weight DNA of the eight patients were then pooled for library construction and HTS was subcontracted to DNA Vision (Charleroi, Belgium) on a HiSeq 2000 instrument (Illumina Inc, San Diego, CA, U.S.A.), generating approximately 120 million reads. Sequences were trimmed and analysed as described previously: overlapping reads were assembled to obtain contiguous sequences (contigs). Nonoverlapping reads (singletons) were also kept for the analysis.…”