The Li-Fraumeni syndrome (LFS): a model for the initiation of p53 signatures in the distal Fallopian tube.

A candidate early precursor to pelvic serous cancer, the 'p53 signature', is commonly found in the benign mucosa of the distal Fallopian tube and harbours p53 mutations and evidence of DNA damage. We examined tubes from women with pre-existing (germ-line) mutations in p53 [Li-Fraumeni syndrome (LFS)] for evidence of this precursor. Fallopian tubes from two cases of LFS were immunostained for p53, Ki-67 (proliferation) and H2AX (DNA damage response) and analysed for p53 mutations by laser capture microdissection (LCM) and p53 genomic sequencing (exons 2-11). A common single nucleotide repeat (snp) in exon 3 (rs1042522) and deletion sequencing chromatograms in exon 4 were examined in combination to estimate LOH in both LFS tubes and advanced serous carcinomas from the general population. LFS tubal epithelium contained abundant (10-20 per section) p53 signatures with evidence of DNA damage and low proliferative activity. Six of 11 LFS microdissected p53 signatures (55%) and 15 of 21 serous carcinomas (71%) revealed LOH at the p53 locus, relative to background epithelium. The LFS model confirms prior observations that the distal Fallopian tube is particularly prone to focal epithelial p53 gene inactivation-p53 mutation and LOH-in the absence of malignancy or increased epithelial proliferation. The fact that the LFS is not associated with ovarian cancers is consistent with the concept that loss of p53 function must be accompanied by at least one more genotoxic event (including BRCA1/2 functional inactivation) to produce the malignant phenotype. This is in keeping with a general model of carcinogenesis, in which different and often independent risk factors operate at multiple points in the serous carcinogenic spectrum.

Intercepting early pelvic serous carcinoma by routine pathological examination of the fimbria.

Recent evidence indicates that the distal fallopian tube is the principal site of early serous cancer in women with a hereditary risk for ovarian cancer. Moreover, the fimbria is involved by early cancer in a significant minority of pelvic serous carcinomas, irrespective of whether the patient has a hereditary BRCA1 or BRCA2 mutation. In addition, the distal tube has been identified occasionally as a site of concurrent endometrioid tumors in women with endometrial carcinoma. Although the risk of sporadic fimbrial tumors in otherwise healthy women without genetic risk is unknown, routine histological examination of the fimbria provides the opportunity to determine the risk of such an event. To illustrate this point, a case of a woman who underwent surgery for an ovarian fibroma is presented. The distal tube was submitted, and found to harbor a focus of serous tubal intraepithelial carcinoma (STIC) with a 2-mm invasive tumor. Incidentally discovered carcinomas underscore the potential risk, albeit low, of concurrent unsuspected malignancy in the distal fallopian tube and emphasize the importance of routine pathological examination of the fimbria in all salpingectomies. The rationale for this strategy, and its potential effect on early detection and in uncovering persons or families potentially at risk for ovarian cancer, is discussed.

Polymerase chain reaction detection of HPV in squamous carcinoma of the oropharynx.

Human papillomavirus (HPV) testing is routinely performed on oropharyngeal carcinomas. We compared the Access Genetics (Minneapolis, MN) polymerase chain reaction (PCR) assay (AGPCR), DNA-DNA in situ hybridization (ISH; Ventana, Tucson, AZ), and HPV-16 E7 PCR amplification in consecutively accessioned oropharyngeal cancers. We tested 126 cases by both PCR methods; 102 were positive by either for a maximum positive rate (MPR) of 81.0%. Relative to the MPR, the sensitivities of AGPCR and E7 PCR were 90.2% and 72.5%, respectively. Of 17 AGPCR+ cases tested by ISH, 14/14 unequivocally positive/negative were concordant. All cases (97/97) positive by either PCR assay were positive for p16. There was no relationship between level of histologic differentiation and HPV status. ISH and AGPCR have comparable performance for the detection of HPV in oropharyngeal carcinomas. PCR is a suitable and economical assay that is comparable to ISH in sensitivity and may provide logistical advantages relative to ISH for assessing HPV status in oropharyngeal malignancies. However, it is imperative that appropriate sensitivity controls be in place for such assays.