Christophe Depuydt

MedCalc: a new computer program for medical statistics

In recent years, the use and abuse of statistics in the medical literature has extensively been reviewed. Amongst others, the importance of the P-value has been challenged and the use of misleading graphics, including 3-dimensional displays, has been criticized. The ease of access to more complex statistical procedures, since the introduction of several statistical software packages for personal computers, has been identified as one of the factors involved in the misuse of statistics. Therefore, we have developed a new computer program that includes those statistical procedures commonly encountered in the medical literature and in statistical textbooks for medical researchers. More complex statistical analyses are not implemented in the software. If researchers with limited statistical training require more sophisticated statistical analyses, they should refer to a statistician, not to a more complete statistical software package.

Comparison of MY09/11 consensus PCR and type-specific PCRs in the detection of oncogenic HPV types

The causal relationship between persistent infection with high‐risk HPV and cervical cancer has resulted in the development of HPV DNA detection systems. The widely used MY09/11 consensus PCR targets a 450bp conserved sequence in the HPV L1 gene, and can therefore amplify a broad spectrum of HPV types. However, limitations of these consensus primers are evident, particularly in regard to the variability in detection sensitivity among different HPV types. This study compared MY09/11 PCR with type‐specific PCRs in the detection of oncogenic HPV types. The study population comprised 15, 774 patients. Consensus PCR failed to detect 522 (10.9%) HPV infections indicated by type‐specific PCRs. A significant correlation between failure of consensus PCR and HPV type was found. HPV types 51, 68 and 45 were missed most frequently. The clinical relevance of the HPV infections missed by MY09/11 PCR was reflected in the fraction of cases with cytological abnormalities and in follow‐up, showing 104 (25.4%) CIN2+ cases. The MY09/11 false negativity could be the result of poor sensitivity, mismatch of MY09/11 primers or disruption of L1 target by HPV integration or DNA degradation. Furthermore, MY09/11 PCR lacked specificity for oncogenic HPVs. Diagnostic accuracy of the PCR systems, in terms of sensitivity (MY09/11 PCR: 87.9%; type‐specific PCRs: 98.3%) and specificity (MY09/11 PCR: 38.7%; type‐specific PCRs: 76.14%), and predictive values for histologically confirmed CIN2+, suggest that type‐specific PCRs could be used in a clinical setting as a reliable screening tool.

P16INK4a as an adjunct marker in liquid‐based cervical cytology

Cytological screening for cervical cancer is hampered by high false negative rates. Inter‐observer reproducibility needs optimizing. The potential of p16INK4a as a biomarker for cervical lesions was examined in a study of liquid‐based cytology (LBC), HPV DNA testing by MY09/MY11 consensus PCR and type‐specific PCRs and p16INK4a immunocytochemistry on a series of 291 patients selected from routine screening. Comparison of the number of p16INK4a immunoreactive cells/1,000 cells exhibited a significantly higher mean count in HSIL (8.80 ± 1.13) than other cytological groups. The mean count of LSIL (1.09 ± 0.18) was significantly higher than that of the negative group (0.82 ± 0.40). ASC‐H and HSIL combined showed a significantly higher mean count (6.46 ± 1.17) than negative, ASC, ASC‐US and LSIL. The mean count of immunoreactive cells/1,000 cells was significantly higher in HPV16 positive samples (3.22 ± 0.72) than in samples containing infections with types of unknown malignant potential (0.83 ± 0.26) or HPV negative samples (1.17 ± 0.41). The mean count in infections with other high‐risk HPV types (2.55 ± 0.52) was significantly higher than that in HPV negative samples. Receiver‐operating characteristic curves yielded a test accuracy (area under curve) of 0.76, 0.79, 0.88 and 0.95 for ASCUS, LSIL, ASC‐H/HSIL and HSIL, respectively. Thresholds for 95% sensitivity were at 0.005, 0.007, 0.098 and 0.445 immunopositive cells/1,000 cells for ASCUS, LSIL, ASC‐H/HSIL and HSIL, respectively. The 95% specificity threshold for the detection of HSIL was at 1.87 immunopositive cells/1,000 cells. P16INK4a immunocytochemistry can be used as an adjunct to LBC in cervical screening, because it has a good diagnostic accuracy to discriminate HSIL and ASC‐H from other lesions. It could be used as a surrogate marker of high‐risk HPV infections.

Are 20 human papillomavirus types causing cervical cancer

In 2012, the International Agency for Research on Cancer concluded that there was consistent and sufficient epidemiological, experimental and mechanistic evidence of carcinogenicity to humans for 12 HPV types (HPV16, HPV18, HPV31, HPV33, HPV35, HPV39, HPV45, HPV51, HPV52, HPV56, HPV58 and HPV59) for cervical cancer. Therefore, these types were considered as 1A carcinogens. They all belong to the family of the α‐Papillomaviridae, in particular to the species α5 (HPV51), α6 (HPV56), α7 (HPV18, HPV39, HPV45, HPV59) and α9 (HPV16, HPV31, HPV33, HPV35, HPV52, HPV58). Less evidence is available for a thirteenth type (HPV68, α7), which is classified as a 2A carcinogen (probably carcinogenic). Moreover, seven other phylogenetically related types (HPV26, HPV53, HPV66, HPV67, HPV68, HPV70 and HPV73) were identified as single HPV infections in certain rare cases of cervical cancer and were considered possibly carcinogenic (2B carcinogens). Recently, Halec et al [7] demonstrated that the molecular signature of HPV‐induced carcinogenesis (presence of type‐specific spliced E6*| mRNA; increased expression of p16; and decreased expression of cyclin D1, p53 and Rb) was similar in cervical cancers containing single infections with one of the eight afore‐mentioned 2A or 2B carcinogens to those in cancers with single infections with group 1 carcinogens. Ninety six percent of cervical cancers are attributable to one of the 13 most common HPV types (groups 1 and 2A). Including the additional seven HPV types (group 2B) added 2.6%, to reach a total of 98.7% of all HPV‐positive cervical cancers. From recently updated meta‐analyses, it was shown that HPV68, HPV26, HPV66, HPV67, HPV73 and HPV82 were significantly more common in cancer cases than in women with normal cervical cytology, suggesting that for these HPV types, an upgrading of the carcinogen classification could be considered. However, there is no need to include them in HPV screening tests or vaccines, given their rarity in cervical cancers. Copyright

Association of HIV infection with distribution and viral load of HPV types in Kenya: a survey with 820 female sex workers.

BackgroundHuman papillomavirus (HPV) and HIV are each responsible for a considerable burden of disease. Interactions between these infections pose substantial public health challenges, especially where HIV prevalence is high and HPV vaccine coverage low.MethodsBetween July 2005 and January 2006, a cross-sectional community-based survey in Mombasa, Kenya, enrolled female sex workers using snowball sampling. After interview and a gynaecological examination, blood and cervical cytology samples were taken. Quantitative real-time PCR detected HPV types and viral load measures. Prevalence of high-risk HPV was compared between HIV-infected and -uninfected women, and in women with abnormal cervical cytology, measured using conventional Pap smears.ResultsMedian age of the 820 participants was 28 years (inter-quartile range [IQR] = 24-36 years). One third of women were HIV infected (283/803; 35.2%) and these women were y more likely to have abnormal cervical cytology than HIV-negative women (27%, 73/269, versus 8%, 42/503; P < 0.001). Of HIV-infected women, 73.3% had high-risk HPV (200/273) and 35.5% had HPV 16 and/or 18 (97/273). Corresponding figures for HIV-negative women were 45.5% (229/503) and 15.7% (79/503). After adjusting for age, number of children and condom use, high-risk HPV was 3.6 fold more common in HIV-infected women (95%CI = 2.6-5.1). Prevalence of all 15 of the high-risk HPV types measured was higher among HIV-infected women, between 1.4 and 5.5 fold. Median total HPV viral load was 881 copies/cell in HIV-infected women (IQR = 33-12,110 copies/cell) and 48 copies/cell in HIV-uninfected women (IQR = 6-756 copies/cell; P < 0.001). HPV 16 and/or HPV 18 were identified in 42.7% of LSIL (32/75) and 42.3% of HSIL (11/26) lesions (P= 0.98). High-risk HPV types other than 16 and 18 were common in LSIL (74.7%; 56/75) and HSIL (84.6%; 22/26); even higher among HIV-infected women.ConclusionsHIV-infected sex workers had almost four-fold higher prevalence of high-risk HPV, raised viral load and more precancerous lesions. HPV 16 and HPV 18, preventable with current vaccines, were associated with cervical disease, though other high-risk types were commoner. HIV-infected sex workers likely contribute disproportionately to HPV transmission dynamics in the general population. Current efforts to prevent HIV and HPV are inadequate. New interventions are required and improved implementation of existing strategies.

Human papillomavirus DNA strongly correlates with a poorer prognosis in oral cavity carcinoma.

The prevalence of human papillomavirus (HPV) in a clinical series of 162 patients with oral squamous cell carcinoma (OSCC) was studied. Furthermore, we analyzed the correlation between the immunohistochemical expression of p16, p53, epidermal growth factor receptor (EGFR), and HPV status to predict survival in OSCC patients.

High incidence of high-risk HPV in benign and malignant lesions of the larynx

The aim of this study was to determine the prevalence of human papillomavirus (HPV) in patients with laryngeal benign lesions (LBLs) and laryngeal squamous cell carcinomas (LSCCs) using a sensitive E6/E7 type-specific PCR. Paraffin-embedded samples from LBL (n=39) and LSCC patients (n=67) were evaluated for the presence of HPV DNA by GP5+/GP6+ consensus PCR and E6/E7 type-specific PCR for HPV types 6, 11, 16, 18, 31, 33, 35, 39, 45, 51, 52, 53, 56, 58, 59, 66 and 68. In LSCCs, immunohistochemical staining of p16, p53 and EGFR was also assessed. The E6/E7 type-specific PCR showed that 44 out of 59 LSCC patients (i.e., 75%) had high-risk (hr) HPV types and that 27 out of 35 LBL patients (i.e., 77%) had hrHPV types. HPV-16 viral load was significantly higher in LSCC than in LBL patients (p<10-6). The presence of hrHPV DNA did not correlate with the proportion of disease-free patients. Comparable levels of p16, p53 and EGFR expression were observed in the hrHPV+ tumor group (100% p16+, 56% p53+ and 97% EGFR+) and in the HPV- or low-risk (lr) HPV+ tumor group (92% p16+, 66% p53+ and 100% EGFR+). A very high prevalence of oncogenic HPV-16 was found in a series of benign and malignant laryngeal lesions. LSCC appears to be characterized by an active hrHPV infection. In LSCCs, the hrHPV+ subgroup had a similar prognosis (in terms of risk of recurrence) as the HPV- subgroup.

Chronic prostatitis and male accessory gland infection--is there an impact on male infertility (diagnosis and therapy)?

The aim of this article was to discuss by means of a review of the literature and own study material the multifactorial aetiology of male infertility, extrapolate this hypothesis to male accessory gland infection (MAGI) and relate it to chronic prostatitis and its treatment. Infertility is a multifactorial disease and diagnosis and therapy must be oriented as such. Although the relationship between prostatitis and infertility remains unclear, bacteria, viruses, leucocytes, reactive oxygen species, cytokines, obstruction and immunological abnormalities must be seen as cofactors in the development of infertility in patients with MAGI and prostatitis. Infection, trauma, allergy, neurogenic damage, chemical or mechanical factors can lead to a long‐lasting inflammation of the prostate or pelvic organs even after eradication of the aetiological agent, and is potentially related to infertility through cytokines. In relation to treatment of infertility, antibiotics play a role in bacterial prostatitis whereas in abacterial prostatitis other treatments like antioxidants, sacral nerve stimulation and anti‐inflammatory treatment are worth to be studied in the future.

The clinical and biologic significance of serum inhibins in subfertile men

Inhibin B is a marker of spermatogenesis and Sertoli cell function. The objective of this study was to evaluate the biologic significance of inhibins in subfertile men and the usefulness of inhibin B for the detection of male reproductive dysfunction. Forty-seven subfertile men were evaluated by semen analysis and clinical examination. In addition to semen analysis and hormone determinations, inhibins A and B (Serotec) in all 47 and inhibin A in 25 of these samples using another kit (Biosource) were measured. Higher inhibin B (median, range: 160.3, 81.8-328.5 pg/mL vs. 94.9, 15.6-389.7 pg/mL, P = 0.024) and lower FSH (P = 0.001) were detected in men with sperm concentrations > or =20 million/mL (n = 9), compared to oligozoospermia (sperm concentration <20 million/mL, n = 38). Inhibin B correlated significantly negatively with FSH, LH, and E2, and patients age and positively with sperm concentration, testicular volume, and TSH. Multiple regression analysis indicated FSH, LH, E2, TSH, and age as the independent variables for inhibin B with a coefficient of determination (R) of 0.53. Simultaneous measurement of both FSH and inhibin B identified more cases with oligozoospermia than either hormone alone. Taking into account the body mass index, the age of the patient, and the indirect mixed antiglobin reaction (MAR) test result in addition to FSH and inhibin B led to the correct semen classification in 45 out of 47 cases. The simultaneous measurement of FSH and inhibin B, taking into account age, body mass index, and the indirect MAR test result appears accurate in identifying subfertility. Inhibin A is detectable in some subfertile men but its significance is not clear.

Mechanisms of sperm deficiency in male accessory gland infection.

Summary. The presence of 2 million or more peroxidase‐positive white blood cells per ml of semen, or the diagnosis of male accessory gland infection, is associated with important biochemical and biological changes in semen plasma and in the spermatozoa, reducing their fertilizing potential in vitro and in vivo (e.g., during intra‐uterine insemination). In addition to the effects of reactive oxygen species, and its influence on the essential fatty acid composition of the sperm membrane, potentially unfavourable effects can occur through the intermediate of increased concentrations of certain cytokines, and decreased activity of enzymes such as alpha‐glucosidase.