Genetic polymorphism of the mannose-binding protein gene in children with sickle cell disease: identification of three new variant alleles and relationship to infections.

Mannose-binding protein (MBP) is a serum lectin that participates in the innate immune response. MBP deficiency may constitute a risk factor in the development of infections. Three MBP structural variants have been identified with a dominant effect on MBP serum concentration. Similarly, polymorphisms in the promoter of the corresponding gene (HSMBP1B) have been related to variations of MBP concentration in serum. Children with sickle cell disease (SCD) have an increased susceptibility to infections with encapsulated organisms resulting in meningitis, septicaemia, and osteomyelitis. We have investigated the HSMBP1B genotype in 242 children with SCD living in Paris. Apart from the known variant alleles, we identified three novel ones and report their distribution in our sample population. In addition, we found rather unexpectedly an increased frequency of the variant alleles in patients who had not suffered severe infections.

Frequency and prognostic significance of HPV DNA in sentinel lymph nodes of patients with cervical cancer.

BACKGROUND: It has been suggested that histologically undetectable or 'occult' metastases in the lymphatic system could explain some recurrences. HPV DNA screening by means of the polymerase chain reaction (PCR) has been proposed as a method to detect occult metastases. This study was designed to determine the frequency of HPV DNA detection by PCR in sentinel lymph node (SN), and its relation to the clinical characteristics and outcome of women with cervical cancer. PATIENTS AND METHODS: The primary cervical tumor and SN were tested for HPV DNA by means of PCR in 59 patients. RESULTS: Fifteen (25.4%) of the 59 women undergoing the SN procedure had an involved SN. HPV DNA was more frequent in positive SN than in negative SN (P < 0.0001). Seven patients had a recurrence, after a mean delay of 17 months (range: 10-26). One of seven patients with a recurrence had an involved SN. HPV DNA was detected in an SN of one of seven patients with recurrence and nine (19.5%) of 46 patients without recurrence (not significant). CONCLUSION: In women with cervical cancer, HPV DNA screening of sentinel nodes might help to identify patients at risk of lymph node metastases and recurrence.

Expression of Bcl-2 protein in human laryngeal keratoses.

Strong Bcl-2 immunostaining was detected in 2 of 21 samples of human laryngeal keratoses, one of which contained neither p53 gene mutation nor human papillomavirus sequences nor significant levels of p53 protein. The other 19 samples including 6 cases with moderate or strong p53 staining were Bcl-2-unreactive or had minimal Bcl-2 reactivity similar to that observed in normal samples. Minimal Bcl-2 staining in 5 samples with moderate or severe dysplasia was only seen in the adjacent nondysplastic area. Our study shows that (1) some laryngeal keratoses strongly express Bcl-2 protein, (2) Bcl-2 expression does not appear to be dependent on p53, and (3) moderate or severe dysplasias may occur despite a decline in Bcl-2 expression.

Loss of heterozygosity on the short arm of chromosome 3 in cervical intra-epithelial neoplasia without concomitant cervical carcinoma.

Losses of heterozygosity on the short arm of chromosome 3p are common in cervical carcinomas in the 3p13-3p21 region, and can be observed in intra-epithelial lesions accompanying cervical cancers. As a preliminary attempt to determine whether these losses can be observed in intra-epithelial cervical lesions without concomitant invasive carcinoma, we have used two microsatellite markers located at the two most frequently deleted segments of the 3p13-3p21 region. We have studied 36 cases of grade II and grade III cervical intra-epithelial neoplasias obtained by conisation biopsies and 30 cases of cervical carcinoma including 3 micro-invasive squamous cell carcinomas. We found loss of heterozygosity or microsatellite instability in 6 of 16 (38%) and 9 of 23 (39%) informative cases of cervical carcinoma at 3p13 and 3p21, respectively. Four of 27 (15%) cases of cervical intra-epithelial neoplasia showed loss of heterozygosity at 3p13, whereas loss of heterozygosity or microsatellite instability at 3p21 was found in 5 of 19 cases (26%). No relationship was found between 3p loss of heterozygosity and human papillomavirus infection. In conclusion, losses of heterozygosity at 3p13 and 3p21 occur in premalignant lesions without concomitant invasive lesions. The prevalence and precise extent of these losses should be established by a more extensive analysis.

Expression of p53 protein related to the presence of human papillomavirus infection in precancer lesions of the larynx.

The aim of this study was to gain some insight into the relationship of human papillomavirus (HPV) infection to p53 expression and to some pathological parameters in precancerous lesions of the larynx. Formalin-fixed paraffin-embedded tissue sections containing human laryngeal precancerous lesions were screened for p53 protein by immunohistochemistry with the monoclonal antibody DO7 and for the presence of HPV infection by polymerase chain reaction with consensus primers directed against the E6 gene. The presence of p53 protein was detected in 31 of 57 specimens (54.4%) including 7 of 9 cases with mild dysplasia (78%), in 4 of 9 cases with moderate dysplasia (44%), and in 15 of 23 cases with severe dysplasia (65%). Of 16 samples with keratotic benign squamous metaplasia, 5 were also p53 positive (31%). Of 6 samples that were HPV positive, all were of type 16. Interestingly, 3 of the 6 HPV-positive samples were p53 negative. There was 1 HPV-positive case with strong p53 staining and 2 HPV-positive cases with minimal p53 staining. The 2 HPV-positive cases with minimal p53 staining had mild dysplasia. The HPV-positive case with strong p53 staining displayed severe dysplasia. Of 23 cases that were both HPV and p53 negative, 11 presented with keratosis and no dysplasia, 5 with moderate dysplasia, and 7 with severe dysplasia. Our data indicate that nuclear accumulation of p53 protein, presumably resulting from p53 gene mutation, may occur in HPV-infected epithelial tissues. On the other hand, there are many precancer lesions, some exhibiting moderate or severe dysplasia, that are both HPV negative and p53 unreactive, suggesting that alterations of genes other than the E6 oncogene and the p53 tumor suppressor gene play a role in early laryngeal carcinogenesis.

Telomerase activation cooperates with inactivation of p16 in early head and neck tumorigenesis.

Alteration of the p16/pRb pathway may cooperate with telomerase activation during cellular immortalization and tumour progression. We studied p16 expression status by immunohistochemistry and telomerase activity using the TRAP assay in 21 premalignant lesions of the head and neck epithelium as well as 27 squamous-cell carcinomas. We also examined expression of other components of the pathway (cyclin D1 and pRb) as well as presence of human papillomavirus genomes which can target these molecules. 4 of 9 mild dysplastic lesions (44%), 8 of 12 moderate/severe dysplastic lesions (67%), and 25 of 27 squamous-cell carcinomas (92%) demonstrated high telomerase activity (P = 0.009). There was a parallel increase with severity of lesions for the trend in proportions of cases demonstrating p16 inactivation or cyclin D1 overexpression (P = 0.02 and P = 0.01, respectively). For Ki67, a marker of cell proliferation, this trend was not significant (P = 0.08). Human papillomavirus infection was only found in 4 cases among the 48 samples tested (8.3%). In conclusion, progression of disease is accompanied by a parallel and continuous increase in telomerase activity and alterations in cell cycle regulators (p16, cyclin D1), as proposed by in vitro models.