Background: Cutaneous leishmaniasis (CL) is a major problem in many tropical and subtropical countries. The clinical diagnosis should be confirmed by identification of the parasite in biopsy or smear or by tissue culture. The sensitivity of direct microscopy is not high, and tissue culture is not uniformly available and successful. Polymerase chain reaction (PCR) is a sensitive test for the detection of low amounts of DNA in tissues. Objective: We applied PCR on paraffin-embedded skin biopsies to assess the validity of this method in the diagnosis of cutaneous leishmaniasis. Methods: DNA extraction from paraffin blocks was performed by the heat method, and PCR was carried out using the primers for the Leishmania-specific 120-base-pair fragment of kinetoplast DNA minicircles. Paraffin blocks of gelatin-embedded formalin-fixed Leishmania tropica, taken from culture, served as positive controls. Negative controls were the skin biopsies of patients whose clinicopathologic diagnoses were not cutaneous leishmaniasis. Results: PCR showed the parasite in all 33 cases whose skin biopsies had shown the Leishmania parasite by light microscopy. PCR results were also positive in 24 cases out of 29 where microscopic examination of skin biopsies had failed to detect the amastigote but their clinical diagnosis was CL. The sensitivity of PCR in the diagnosis of CL was 92%. None of the nonleishmaniasis cases showed positive results (specificity 100%). PCR results were positive in 52 out of 54 cases whose skin biopsies showed granulomatous inflammation. Evaluation of the histopathologic findings showed that the presence of vaguely formed immature granuloma was directly and the detection of mature well-formed granuloma was inversely correlated with the detection of the parasite in biopsies (p < 0.01). Conclusion: PCR on paraffin-embedded tissue is a highly sensitive and specific test for the diagnosis of CL, and detection of granulomatus inflammation is a highly reliable histopathologic finding in suspected cases.

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Viruses including Epstein-Barr virus (EBV), JCV and BKV have been reported to be associated with some cancers. The association of these viruses with colorectal cancers remains controversial. Our objective was to investigate their infections association with adenocarcinoma and adenomatous polyps of the colon. Totally, 210 paraffin-embedded tissue specimens encompassing 70 colorectal adenocarcinoma, 70 colorectal adenomatous and 70 colorectal normal tissues were included. The total DNA was extracted, then qualified samples introduced to polymerase chain reaction (PCR). The EBV, JCV and BKV genome sequences were detected using specific primers by 3 different in-house PCR assays. Out of 210 subjects, 98 cases were female and the rest were male. The mean age of the participants was 52 ± 1.64 years. EBV and JCV DNA was detected just in one (1.42%) out of seventy adenocarcinoma colorectal tissues. All adenomatous polyp and normal colorectal tissues were negative for EBV and JCV DNA sequences. Moreover, all the patients and healthy subjects were negative for BKV DNA sequences. The results suggested that EBV and JCV genomes were not detectable in the colorectal tissue of patients with colorectal cancer in our population. Hence, BKV might not be necessitated for the development of colorectal cancer. The findings merit more investigations.

Background: Colorectal cancer is one of the most common cancers worldwide. Viruses including human papillomavirus (HPV) have been reported to be associated with different cancers but any association with colorectal cancers remains controversial. Aim: To evaluate any association between HPV infection and adenocarcinoma of the colon and adenomatous polyps. Materials and Methods: Paraffin-embedded tissue specimens of 70 colorectal adenocarcinomas, 70 colorectal adenomatous polyps, and 70 colorectal normal tissues were subjected to DNA extraction. The quality of the extracted DNA was confirmed by amplification of a β-globin fragment using polymerase chain reaction (PCR). PCR using specific primers were performed to detect HPV DNA. Specific primers targeting the E6 region of the HPVs 16 and 18 were used for genotyping. Results: HPV DNA was detected in 2 (2.85%) out of 70 adenocarcinoma colorectal tissues and 4 (5.71 %) out of 70 adenomatous colorectal tissues. All normal colorectal tissues were negative for HPV DNA. HPV-16 was the most predominant genotype (5 sample) followed by HPV-18 (4 sample). Despite the above observations, statistical analyses indicated no significant differences in the frequencies of HPV positive subjects between the cancerous and normal samples. Conclusions: Although the differences observed in the frequencies of HPV positive cases in our study was not significant relative to those of control subjects, the fact of 6 positive samples among cancerous tissues, may still suggest a role of HPV in colorectal carcinogenesis. The study collectively indicated that some colorectal cancerous tissues are infected with high risk HPV genotype. The findings merit more investigation.