Sir,High-risk human papilloma viruses (HPVs) have been consistently identified in 13 -86% of breast tumours in the 10 studies published since 1999 (Lawson et al, 2006). High-risk HPVs of the same type have been identified in both cervical and breast cancer that had occurred in the same women (Hennig et al, 1999;Widschwendter et al, 2004). This observation has lead to the hypothesis that HPVs may be transmitted to the breast during sexual activities (Kan et al, 2005). If this hypothesis is correct, it is likely that HPV-positive breast cancers would occur in women younger than those with HPV-negative breast cancer. This is because HPV genital infections are much more common in young women who have had multiple sexual partners (IARC, 1995).There are only two studies in which the age of women with HPV-positive and -negative breast cancer has been published. There were no differences in the average of age of women with either HPV-positive and -negative breast cancer in a study of Brazilian women (Damin et al, 2004). This is in contrast to a recent study of Greek women in which those with HPV-positive breast cancer were of average age 38 years as compared to average age 53 years for women with HPV-negative breast cancer (P-values for difference ¼ 0.001) (Kroupis et al, 2006).We have reviewed the ages of Australian women with HPVpositive and -negative breast cancer in our study published in this Journal (Kan et al, 2005). These data are shown in Table 1. The average age of women with HPV-positive breast cancer was 55.6 years as compared to 63.8 years for women with HPV-negative breast cancer (P-values for difference ¼ 0.049). These data are compatible with the hypothesis that HPV-positive breast cancers occur in younger women than those with HPV-negative breast cancers, and that high-risk HPVs may have been transmitted by sexual activity with HPV-positive sexual partners. HPV ¼ human papilloma virus. P-value for difference in average ages ¼ 0.049, which is significant at the 95% level.
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BackgroundMouse mammary tumour viruses (MMTVs) may have a role in a subset of human breast cancers. MMTV positive human breast cancers have similar histological characteristics to neuroendocrine breast cancers and to MMTV positive mouse mammary tumours. The purpose of this study was to investigate the expression of neuroendocrine biomarkers – synaptophysin and chromogranin, to determine if these histological characteristics and biomarker expression were due to the influences of MMTV.MethodsImmunohistochemistry analyses to identify synaptophysin and chromogranin were conducted on a series of human breast cancers in which (i) MMTV had been previously identified and had similar histological characteristics to MMTV positive mouse mammary tumours and (ii) MMTV positive mouse mammary tumours.ResultsThe expression of synaptophysin and chromogranin in MMTV positive mouse mammary tumors were all positive (7 of 7 specimens – 100% positive). The expression of synaptophysin and chromogranin in MMTV positive human breast cancers was much less prevalent (3 of 22 – 14%). There was no expression of synaptophysin and chromogranin in the normal breast tissue control specimens.DiscussionIt is not possible to draw any firm conclusions from these observations. However, despite the small numbers of MMTV positive mouse mammary tumours in this study, the universal expression in these specimens of synaptophysin and chromogranin proteins is striking. This pattern of synaptophysin and chromogranin expression is very different from their expression in MMTV positive human breast cancers. The reason for these differences is not known.ConclusionsThe high prevalence of positive expression of synaptophysin and chromogranin in MMTV positive mouse mammary tumours and low expression of synaptophysin and chromogranin in MMTV positive human breast cancers indicates that MMTV is not usually associated with neuroendocrine human breast cancers.Electronic supplementary materialThe online version of this article (doi:10.1186/s13027-017-0135-8) contains supplementary material, which is available to authorized users.
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