In reference to the Letter to the Editor “Can hair be used to screen for breast cancer?” (J Med Genet2000;37:297-8), I must bring attention to a fatal flaw in the experimental data and hence the conclusions reached by Howell et al.1 If their figure is a representative example of a typical image used in their analyses, I must conclude that there is no way that this group could test our assertion that there appears to be a strong correlation between a change in the x ray diffraction pattern of hair and the onset of breast cancer.2

The image shown by Howell et al 1 contains none of the features that must be present in a diffraction pattern of hair if any meaningful analysis is to be performed. Specifically, in even a rudimentary image of a single hair or bunch of hairs the strongest meridional reflections should be very obvious at the 6.71 nm and 2.47 nm positions. In all of our studies (including a number done subsequent to the publication of theNature paper), we found that the ring corresponding to breast cancer was less intense than these 7th and 19th meridionals. Furthermore, when we did measure an anomalously intense diffuse ring, it was found to lie at a slightly different position (clearly not resolvable with the images used by Howellet al 1) and invariably disappeared when the sample alignment was improved and the hair put under an appropriate amount of tension. A diffraction image of a properly aligned and tensioned single hair with all the appropriate meridional reflections clearly visible can be seen in Wilket al.3 The section of interest in the diffraction pattern for a normal hair sample is shown in fig 1A and that for the hair of a breast cancer patient is shown in fig1B.

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Figure 1

(A) A fibre diffraction intensity pattern for hair taken from a control showing the very strong 7th, 19th, and 38th orders of the 47 nm meridional lattice. (B) A fibre diffraction intensity pattern for hair taken from a breast cancer patient showing that the intensity of the diffuse ring reported as associated with all breast cancer patients is less intense than the three strong meridional reflections.

In conclusion, I must state that poor alignment, poor signal to noise, and poor resolution rendered the diffraction images of Howellet al 1 useless for this type of analysis. As a final note, I would like to emphasise that ourNature paper was based on a study of 56 samples including both scalp and pubic hair and not just on 12 samples as asserted by Howell et al.