Comparative analysis of human papillomavirus detection by dot blot hybridisation and non-isotopic in situ hybridisation

Cyclin dependent kinase inhibitor p27Kip1 expression in normal and neoplastic cervical epithelium

AIM

To investigate whether there is loss of the p27Kip1 protein in developing cervical cancer and whether p27Kip1 immunoreactivity has any relation to the proliferative indicator Ki-67.

METHODS

The expression of p27Kip1 and Ki-67 was assessed by immunohistochemistry in serial sections from normal epithelium (13), low grade (27) and high grade (19) squamous intraepithelial lesions (LSIL, HSIL), and invasive cervical cancer (23). In the SIL cases the presence of human papillomavirus (HPV) genomic sequences was assessed by in situ hybridisation. The results were evaluated by image analysis, and reported as mean score of the percentage of p27Kip1 and of Ki-67 positive cells in each histological group.

RESULTS

In general, p27Kip1 immunostaining was related to squamous differentation, and was intense in normal epithelium (47%), while it was reduced in SIL lesions as an effect of the decreased number of differentiating cells. However, decrease in the p27Kip1 expression was more evident in LSIL (36%) than in HSIL (39%); in the latter, p27Kip1 had a different intraepithelial distribution in that the staining extended to the basal cells. The average levels of p27Kip1 were similar in SIL lesions associated to low, intermediate, and high risk HPV types. Compared with normal epithelium and dysplasia, invasive cancer showed significantly lower p27Kip1 levels (23%). There was no relation between p27Kip1 and Ki-67 labelling indices in any of the histological groups examined.

CONCLUSIONS

A reduction in p27Kip1 protein occurs in cervical cancer independently of the proliferative status. The changes in p27Kip1 expression may be related to the unregulated kinetics of developing cervical cancer.

Flash pump dye laser treatment of laryngeal papillomas

To evaluate the feasibility and safety of the flash pump dye (FPD) laser for the treatment of laryngeal papillomas, we performed a prospective nonrandomized trial comparing FPD and carbon dioxide (CO2) laser treatment of laryngeal papillomas in a tertiary care children's hospital. Nine patients from 2 to 20 years of age with severe recurrent laryngeal papillomas were enrolled in the study. All patients underwent CO2 laser debulking of papillomas on the left hemilarynx, with 8 W continuous or pulsed energy. The right hemilarynx was treated with the FPD laser with 12 to 77 pulses at 8 to 12 J, through a custom-designed 90 degrees firing fiber. An end point of blanching and purpura of the papillomas was used. The main outcome measures were the safety and ease of operation with the FPD laser, and decreased papilloma size based on visual inspection at 2 weeks postoperative and at the next laser procedure. Seven patients were irradiated I time with an FPD laser, and 2 patients 2 times. No intraoperative complications were noted. One patient developed early postoperative stridor. No patients described more discomfort, and 5 patients described their voice as being the same as or better than it was after prior CO2 laser procedures. Five patients had a 90% or more decrease in size of papillomas on the FPD-irradiated side 2 weeks postoperatively. Three patients had approximately a 50% reduction. A treatment effect was noted in all patients, and was similar to the results noted on the CO2 laser-treated side. Early results with FPD laser treatment of laryngeal papillomas suggest the protocol is relatively safe and feasible. Long-term results are pending. Because the FPD laser coagulates rather than vaporizing tissue, potential advantages may include decreased scarring relative to CO2 laser treatment, and improved patient and operator safety.

Immunohistochemical expression of mdm2 and p21WAF1 in invasive cervical cancer: correlation with p53 protein and high risk HPV infection

AIM

To investigate the immunocytochemical staining pattern of mdm2 and p21WAF1 proteins in invasive cervical cancer and to determine its relation with the expression of p53 and with the high risk HPV infection.

METHODS

Immunocytochemistry for p53, mdm2, and p21WAF1 was performed in 31 paraffin embedded sections of invasive cervical cancer. The results were assessed by image analysis, evaluating for each protein the optical density of the immunostained area, scored as percentage of the total nuclear area. The presence of high risk human papillomavirus (HPV) infection was detected by using the polymerase chain reaction.

RESULTS

Immunostaining for both mdm2 and p21WAF1 was correlated with p53 expression; however, the correlation between p53 and mdm2 (R = 0.49; p < 0.01) was more significant than between p53 and p21WAF1 (R = 0.31; p < 0.05); the less stringent correlation between p53 and p21WAF1 might reflect the p53 independent mechanisms of p21WAF1 induction. Similar average levels of p53, mdm2, and p21WAF1 immunostaining were found in the presence or absence of high risk HPV-DNA, without significant differences between the two groups.

CONCLUSIONS

These data suggest that mdm2 and p21WAF1 proteins are expressed in invasive cervical cancer and that their immunocytochemical staining pattern is not abrogated by the presence of high risk HPV genomic sequences.

Detection of human papillomavirus in esophageal squamous cell carcinoma

BACKGROUND

Human papillomavirus (HPV) DNA has been identified in esophageal carcinomas. However, the incidence of HPV varies significantly in different geographic locations. In the current study, neoplasms from two separate geographic regions were analyzed for the presence of HPV DNA:

METHODS

One hundred and ten esophageal squamous cell carcinomas, 83 from Beijing, China and 27 from Cincinnati, Ohio, were examined for the presence of HPV DNA: In situ hybridization and polymerase chain reaction (PCR) using both consensus primers for the HPV L1 gene and type specific primers for the E6 gene of HPV types 6, 16, and 18 were performed.

RESULTS

In situ hybridization failed to demonstrate any HPV type (6, 11, 16, 18, 31, 33, or 35) in any tumor specimen. Likewise, PCR using consensus primers for the HPV L1 gene was negative in all samples. Three of the Chinese specimens (4.29%) were positive for HPV using E6 type specific primers. One tumor contained HPV type 6 DNA, whereas the other 2 contained HPV type 16 DNA. One Cincinnati tumor (4.35%) was positive for HPV 16 by type specific primer. None of the specimens contained HPV 18 DNA.

CONCLUSIONS

The incidence of HPV DNA in esophageal carcinoma specimens from Beijing, China and Cincinnati, Ohio is similar. The incidence of HPV in tumors from Beijing is significantly lower than that reported for those from other regions of China where the incidence of esophageal cancer is higher. Thus, although HPV may play a role in esophageal carcinogenesis, this role may be more pronounced in those regions of the world with a high incidence of the disease, and may be less important in areas with moderate or low risks for esophageal cancer.

Detection of human papillomavirus in esophageal squamous cell carcinoma

BACKGROUND

Human papillomavirus (HPV) DNA has been identified in esophageal carcinomas. However, the incidence of HPV varies significantly in different geographic locations. In the current study, neoplasms from two separate geographic regions were analyzed for the presence of HPV DNA:

METHODS

One hundred and ten esophageal squamous cell carcinomas, 83 from Beijing, China and 27 from Cincinnati, Ohio, were examined for the presence of HPV DNA: In situ hybridization and polymerase chain reaction (PCR) using both consensus primers for the HPV L1 gene and type specific primers for the E6 gene of HPV types 6, 16, and 18 were performed.

RESULTS

In situ hybridization failed to demonstrate any HPV type (6, 11, 16, 18, 31, 33, or 35) in any tumor specimen. Likewise, PCR using consensus primers for the HPV L1 gene was negative in all samples. Three of the Chinese specimens (4.29%) were positive for HPV using E6 type specific primers. One tumor contained HPV type 6 DNA, whereas the other 2 contained HPV type 16 DNA. One Cincinnati tumor (4.35%) was positive for HPV 16 by type specific primer. None of the specimens contained HPV 18 DNA.

CONCLUSIONS

The incidence of HPV DNA in esophageal carcinoma specimens from Beijing, China and Cincinnati, Ohio is similar. The incidence of HPV in tumors from Beijing is significantly lower than that reported for those from other regions of China where the incidence of esophageal cancer is higher. Thus, although HPV may play a role in esophageal carcinogenesis, this role may be more pronounced in those regions of the world with a high incidence of the disease, and may be less important in areas with moderate or low risks for esophageal cancer.

Comparative analysis of human papillomavirus detection by PCR and non-isotopic in situ hybridisation

AIMS--To assess the relative diagnostic performance of the polymerase chain reaction (PCR) and non-isotopic in situ hybridisation (NISH) and to correlate these data with cytopathological assessment. METHODS--Paired analysis of human papillomavirus (HPV) detection was performed by PCR and NISH on exfoliated cervical cells from 122 women attending a routine gynaecological examination. PCR amplification followed by generic and HPV type specific hybridisation was compared with NISH on a parallel cervical smear. RESULTS--Overall, 32 cases were positive by NISH and 61 positive by PCR. Of the 105 cases in which both PCR and NISH were interpretable, 76 (26%) were normal smears, 20 of which were HPV positive by NISH and 37 (49%) by PCR. Of 17 borderline smears, two were NISH positive and 12 PCR positive. Eight of nine smears containing koilocytes were positive by NISH and seven by PCR. Of three dyskaryotic smears, none were NISH and two were PCR positive. The concordance of NISH and PCR in these samples was 57%. To assess sampling error, NISH and PCR were performed on an additional 50 cases using aliquots from the same sample. This increased the concordance between assays to 74%. Filter hybridisation of PCR products with the cocktail of probes used in NISH (under low and high stringency conditions) demonstrated that several cases of NISH positivity could be accounted for by cross-hybridisation to HPV types identified by PCR but not present in the NISH probe cocktail. CONCLUSIONS--Sampling error and potential cross-hybridisation of probe and target should be considered in interpretation of these techniques. PCR is more sensitive because it provides for the amplification of target DNA sequences. In addition, the PCR assay utilised in this study detects a wider range of HPV types than are contained in the cocktails used for NISH. However, PCR assays detect viral DNA present both within cells and in cervical fluid whereas NISH permits morphological localisation.

Squamous cell papillomas of the esophagus: a study of 23 lesions for human papillomavirus by in situ hybridization and the polymerase chain reaction

This study assessed squamous cell papillomas of the human esophagus for the presence of human papillomavirus (HPV) and correlated the results with histological features. Twenty-three lesions obtained by endoscopic biopsy from 17 patients were studied, first by in situ hybridization (ISH) for HPV types 6-11, 16-18, 18, and 31-33-51, and second by the polymerase chain reaction (PCR) with amplification of multiple HPV types and demonstration of amplified product by ethidium bromide staining and Southern blot hybridization for HPV types 6-11, 16, and 18 in each case. Evidence of HPV DNA was found in only one lesion, which showed HPV type 6-11 by ISH and HPV positivity by Southern blotting of the amplified product after the PCR. This case exhibited histological features suggestive of HPV infection, although no morphological changes specific to the lesion were identified. The remaining 22 lesions, including those from cases in which multiple papillomas were present, were negative for HPV. The results show that HPV DNA is frequently not detectable in esophageal squamous cell papillomas, even when highly sensitive techniques are used. These findings are consistent with the hypothesis that other pathogenetic mechanisms, such as mucosal injury and repair, are important in the etiology of these lesions.