Regrettable Omission

LETTERS TO THE EDITOR Regrettable Omission To the Editor: I would like to draw your readers’ attention to the fact that the article by Iwanaga et al titled “Regulation of alternative splicing of caspase-2 through an intracellular signaling pathway in response to pro-apoptotic stimuli”1 did not cite previous work from our group, although that article would appear to build on our earlier observations. We had shown that etoposide was able to trigger caspase-2 alternative mRNA splicing in U937 cells, among other cells.2,3 Iwanaga et al reported the same observations using the exact same PCR approach (and the same primers) and similar kinetics with RNA from etoposide-treated U937 cells. Of course, we are pleased to have our results confirmed by another group. However, even though these authors brought in additional information, we feel that they should have at least mentioned the previously published results, and we are quite disappointed by the omission. Laurent Corcos, PhD Faculté de Médecine Université de Bretagne Occidentale INSERM U613/EA948 22 Avenue Camille Desmoulins 29238 Brest Cedex, France

REFERENCES

1. Iwanaga N, Kamachi M, Aratake K, Izumi Y, Hiroaki I, Fumiko T, et al. Regulation of alternative splicing of caspase-2 through an intracellular signaling pathway in response to pro-apoptotic stimuli. J Lab Clin Med 2005;145:105–10.

2. Solier S, Lansiaux A, Logette E, Wu J, Soret J, Tazi J, et al. Topoisomerase I and II inhibitors control caspase-2 pre-messenger RNA splicing in human cells. Mol Cancer Res 2004;2:53– 61. 3. Wotawa A, Solier S, Logette E, Solary E, Corcos L. Differential influence of etoposide on two caspase-2 mRNA isoforms in leukemic cells. Cancer Lett 2002;185:181–9.

Same splice, different mechanism To the Editor: We reported that phosphatase activation is involved in etoposide-induced alternative splicing of caspase-2.1 This mechanism differs from the mechanism previously reported by Corcos’ group.2 However, we used the same methodology as Corcos’ group, and we should have cited their articles.2 Katsumi Eguchi, MD Makoto Kamachi, MD Nozomi Iwanaga, MD Kouichirou Aratake, MD The First Department of Internal Medicine Graduate School of Biomedical Science, Nagasaki University REFERENCES

1. Iwanaga N, Kamachi M, Aratake K, et al. Regulation of alternative splicing of caspase-2 through intracellular signaling pathway in response to pro-apoptotic stimuli. J Lab Clin Med 2005;145: 105–10. 2. Wotawa A, Solier S, Logette E, Solary E, Corcos L. Differential influence of etoposide on two caspase-2 mRNA isoforms in leukemic cells. Cancer Lett 2002;185:181–9.

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