PURPOSE
The incidence of penile cancer is four times higher in Paraguay than in the United States or Europe. There are no adequate scientific explanations for this geographical variation. The goal of this study was to evaluate the interplay among risk factors, morphology of the primary tumor, and HPV status.
METHODS
Information on socioeconomic status, education level, habits, and sexual history was obtained in 103 Paraguayan patients with penile cancer. All patients were then treated by surgery and specimens were evaluated histopathologically.
RESULTS
Patients usually dwelled in rural/suburban areas (82%), lived in poverty (75%), had a low education level (91%), and were heavy smokers (76%). Phimosis (57%), moderate/poor hygienic habits (90%), and history of sexually-transmitted diseases (74%) were frequently found. Patients with >10 lifetime female partners had an odds ratio of 3.8 (95% CI 1.1, 12.6; P-trend = .03) for presenting HPV positive tumors when compared to patients with <6 partners. However, this trend was not significant when the number of sexual partners was adjusted for age of first coitus and antecedents of sexually-transmitted diseases. HPV-related tumors (found in 36% of the samples) were characterized by a warty and/or basaloid morphology and high histological grade in most cases.
CONCLUSIONS
In our series, patients with penile cancer presented a distinctive epidemiological and pathological profile. These data might help explaining the geographical differences in incidence and aid in the design of strategies for cancer control in Paraguay.
The protein expression of the cyclin-dependent kinase inhibitor p27 is often deregulated in human tumors. In lymphomas the inactivation of p27 is achieved through either increased degradation(1) or sequestration via D cyclins,(2) and p27 protein levels have been shown to have a prognostic significance.(1,3) Recently, S-phase kinase-associated protein 2 (Skp2) has been proved to mediate p27 degradation in normal cells(4-7) and to have oncogenetic properties.(8,9) In this study, B-, T-, and myeloid hematopoietic cell lines and a well-characterized panel of human lymphomas (n = 244) were studied for the expression of Skp2. In human lymphomas, the expression of Skp2 strongly related to the grade of malignancy, being low in indolent tumors and very high in aggressive lymphomas. Moreover, the percentages of Skp2- and S-phase-positive cells, as measured by DNA content or BrdU labeling, strictly matched and closely parallel that of Ki-67 and cyclin A. An inverse correlation between Skp2 and p27 was found in the majority of lymphoma subtypes. Nonetheless, most mantle cell lymphomas and a subset of diffuse large cell lymphomas failed to show this correlation, suggesting that alternative pathway(s) for the regulation of p27 might exist. The detection of Skp2 protein either by flow cytometry or by immunohistochemistry represents a simple method to precisely assess the S phase of lymphomas. The potential diagnostic and prognostic value of Skp2 is discussed.
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