Mature -T- Cell Neoplasms
Anaplastic large cell lymphoma: t(2;5)(p23;q35) and variants, ALK Dual Colour, Break Apart Rearrangement Probe,
T-Cell Prolymphocytic leukaemia (T-PLL): Inv(14)(q11q32) Trisomy for chromosome 8, TCR alpha/delta Dual Colour Break apart Rearrangement Probe, CEP 8 Spectrum Orange/Aqua.
1. T-cell PLL. This is an aggressive T-cell leukaemia. The most frequent chromosome abnormalities in T-PLL involve inversion of chromosome 14, at breakpoints q11 and q32 seen in about 80% of patients. A variant of this, the t(14;14)(q11;q32) also exists. Both of these juxtapose the TCRA locus with the oncogenes TCL1A and TCL1B at 14q32. Abnormalities of chromosome 8 are also seen in addition to ETV6 AND TP53 deletion. The course of this case is aggressive with a median survival of less than one year.
2. Natural NK-cell leukaemia. A systemic neoplastic proliferation of natural killer cells associated with Epstein Barr Virus (EPV). A variety of clonal cytogenetic abnormalities have been reported such as deletions of the long arms of 6 and 11. An iso 7q and trisomy 8 have also been reported.
3. Adult T-cell leukaemia/lymphoma (ATLL). This is associated with the human retrovirus (HTLV-1) and involves rearrangement of t-cell receptor genes. Prognosis is poor.
4. Hepatosplenic T-cell Lymphoma (HSTL). This is a systemic lymphoid neoplasm and the clinical course is aggressive with a median survival of less than two years. TCR genes are rearranged and iso7q is present cytogenetically in most cases as well as other abnormalities of 7q. Trisomy 8 or loss of a sex chromosome can also be seen.
5. Mycosis Fungoides. This is an epidermotrophic T-cell lymphoma. Complex karyotypes are present in many patients in particular in the advanced stages. T-cell receptor genes are rearranged.
6. Anaplastic large cell lymphoma (ALCL),ALK-positive. This is a T-cell lymphoma where in approximately 90% of cases show a rearrangement of the ALK gene at 2p23. This rearrangement can take the form of a translocation or inversion. The most common translocation is the t(2;5)(p23;q35) (ALK/NPM1) and can readily be detected with FISH probes. The prognosis is favourable compared to ALK negative cases.
All samples must be delivered to the laboratory within 24 hours of collection.
Blood Sciences Laboratory
Ground Floor Bessemer Wing
King’s College Hospital
London SE5 9RS
Last updated: 03/07/2017