A previous study featured in the IJC proposed a compelling link between the development of breast cancer and changes in hair composition. This study and others triggered immediate interest since they promised that the analysis of a single hair could replace or complement more aggressive diagnostic tools such as mammography. Instead of the breast itself, individual hair cut from the scalp or the pubic area is exposed to an X-ray beam in a synchrotron accelerator. This X-ray diffraction method revealed changes in the hair of women with breast cancer as well as in whiskers of mice with experimentally implanted breast tumors. Interestingly, the characteristic hair alterations were detectable before the breast tumors became clinically apparent. However, follow-up studies failed to reproduce the data of James and colleagues (Int J Cancer, 114, 2005), and the method became controversial. In the current issue of the IJC, Corino and colleagues revisited the concept of X-ray studies of hair as a diagnostic tool for breast cancer. This new study concludes that an altered diffraction pattern of hair correlates indeed with the presence of breast cancer, but that careful attention must be paid to the handling and analysis of samples. For example, it is critical to apply as little tension and stretching to the hair as possible and to avoid treatment with organic acids that reduce the characteristic diffraction pattern, excluding dyed hair from the analysis (see Figure). What causes the intriguing hair changes remains unknown. The authors speculate that extraneous lipids may be incorporated into hair as a result of the breast tumor. With the new methodological knowledge that has accrued, thorough validation studies are now warranted to ascertain X-ray analyses of hair as a sensitive and specific diagnostic tool for early breast cancer detection, together with investigations of the underlying biological mechanism for such a relationship. YKL-40 is a secreted glycoprotein with structural similarities to digestive enzymes in bacteria that break down glycosidic bonds in chitin. However, this enzymatic activity is missing in YKL-40, and its function is largely unknown. The protein is secreted by immune cells, including tumor-associated macrophages, and is expressed in normal and malignant epithelial cells of the breast. Serum levels of YKL-40 are elevated in patients affected with a variety of solid and hematological tumors, but its relevance for cancers of the oral cavity, the larynx and the pharynx remains to be determined. In the United States, more than 30,000 men and women are diagnosed with squamous carcinoma of the head and neck each year, and only 60% of them survive 5 years after the diagnosis. Roslind and colleagues report that measurements of serum YKL-40 can help predict survival in this group of cancer patients. In a retrospective study, they found that levels of YKL-40 were elevated in more than 50% of patients with cancer of head or neck and were associated with short recurrence-free survival and short overall survival. Interestingly, serum YKL-40 levels did not correlate with common clinical parameters such as primary tumor or nodal status. The new biomarker may therefore reflect unique aspects of tumor growth, invasion and metastasis, possibly linked to tumor-associated immune cells as markers of disease activity in these patients. Relatives of patients with prostate cancer are very concerned about their own risk of prostate cancer. However, it is estimated that an inherited disease factor is involved in only 5–10% of all prostate cancer cases. Hereditary prostate cancer is diagnosed when at least 3 first-degree relatives are affected. If 2 first-degree relatives are diagnosed, prostate cancer has to occur at an early age (≤55 years) to classify as hereditary. Nevertheless, it is commonly believed that the risk in men with a family history of prostate cancer is up to 5-fold enhanced and that “familial” cancers are more aggressive than sporadic cases. Kiemeney and colleagues examined the risk of prostate cancer in unaffected men from families that fulfilled the criteria for hereditary prostate cancer. They found that the detection rate of prostate cancer in these families was similar to the detection rate in men with no family history (2.3%). Based on their results, a more aggressive screening protocol in families with hereditary prostate cancer seems unjustified. The authors refrain from recommending a more lenient screening protocol until larger studies have confirmed their results.