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Oncology: T. Kubo, T. Sugita, S. Shimose, T. Matsuo, K. Arihiro, and M. Ochi Expression of hypoxia-inducible factor-1 and its relationship to tumour angiogenesis and cell proliferation in cartilage tumours J Bone Joint Surg Br 2008; 90-B: 364-370 [Abstract] [Full text] [PDF]

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Inappropriate use of a chi-squared test and the Fisher exact test

Yu-Min Lin, Kun-Hui Chen, Tu-Sheng Lee   (20 March 2008)

Inappropriate use of a chi-squared test and the Fisher exact test 20 March 2008
Yu-Min Lin, Orthopaedic surgeon Department of Orthopaedics, Taichung Veterans General Hospital, Taichung, Taiwan, Kun-Hui Chen, Tu-Sheng Lee Send letter to journal: Re: Inappropriate use of a chi-squared test and the Fisher exact test ymlin{at}vghtc.gov.tw Yu-Min Lin, et al.	Sir, We read this paper with interest. The authors have suggested that hypoxia-inducible factor-1a (HIF-1a) may be a useful objective prognostic marker in chondrosarcoma.1  However, to our dismay, they analysed the correlation of HIF-1a with the microvessel density (MVD), proliferating cell nuclear antigen (PCNA) index and histological grade with Fisher's exact test and the chi-squared test (Table II).  Comparative immunohistochemical staining studies commonly produce matched data because all the different methods of staining sections under comparison are performed on each tissue block (each subject).1  We analysed the association of HIF-1a with MVD, PCNA index and histological grade with the exact form of the McNemar test1,2, and we found no statistically significant association (p-value = 0.077, 0.118, 0.302, respectively).  The association between HIF-1a expression and high MVD is still unsettled because of the limited sample size in the current study.  A further study of a larger scale is needed.  Kun-Hui Chen, MD, Tu-Sheng Lee, MD, PhD, Yu-Min Lin, MD, MMS, Department of Orthopaedics, Taichung Veterans General Hospital, Taichung, Taiwan. 1. Dwyer AJ. Matchmaking and McNemar in the comparison of diagnostic modalities. Radiology 1991;178:328-30. 2. Petrie A. Statistics in orthopaedic papers. J Bone Joint Surg [Br] 2006;88-B:1121-36.