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Alterations of the cell adhesion molecule E-cadherin have been demonstrated in sporadic and hereditary gastric carcinomas. A cell adhesion molecule with functional similarity to E-cadherin is desmoglein 2 (Dsg2), a major component of the desmosomes. In this study, we investigated whether alterations of Dsg2 are involved in gastric carcinogenesis and whether germline mutations contribute to a genetic predisposition in familial gastric cancer patients with no germline mutations in the E-cadherin gene. Seventy-five formalin-fixed, paraffin-embedded tissues from 37 familial and 38 sporadic gastric carcinomas were analysed for Dsg2 expression by immunohistochemistry. DNA from 31 familial gastric cancer patients was analysed for germline mutations and five sporadic tumours were analysed for somatic mutations by DHPLC. Of the 75 tumours, 25 (33%) demonstrated abnormal (reduced and/or non-membrane-associated) Dsg2 expression. There was a trend towards more frequent abnormal expression in diffuse type (42%) than in intestinal type tumours (18%) (p = 0.066). One germline missense variant leading to a non-conservative amino acid change (c. 2810 C > A, Thr 937 Asn) was found in a familial gastric cancer patient with a diffuse type tumour. No somatic mutations were identified. The observed abnormal expression of Dsg2 protein suggests that this molecule is involved in the carcinogenesis of a subset of gastric carcinomas, in particular of the diffuse type. Somatic mutations in the gene do not seem to be a very frequent inactivation event and the finding of no clear pathogenic germline mutation rules out Dsg2 as a major gastric cancer predisposition gene.

Archival paraffin-embedded tumor specimens offer a wealth of information for both cancer research and for routine clinical applications. However, the use of formalin-fixed, paraffin-embedded specimens for quantitative real-time PCR is not yet a standard diagnostic method in many laboratories, in particular for the quantification of human papillomavirus (HPV). Particularly high-risk HPV types are involved in almost 100% of the carcinogenesis of cervical cancer. We compared the diagnostic applicability and sensitivity of real-time PCR to that of chromogenic tyramide-signal-amplified in situ hybridization and conventional PCR for the detection of HPV from archival tissue in 164 cases of carcinoma in situ and cervical cancer. Furthermore, we examined whether the viral load of HPV is of prognostic relevance. Our findings indicate that patients in tumor stage I with a lower viral load of HPV type 16 (HPV16; up to 1,000 copies/ng of DNA) had a significantly better survival than HPV 16-negative patients (P ‫؍‬ 0.037). We observed a greater sensitivity of both real-time PCR and conventional PCR for the detection of HPV16 and -18 compared to signal amplified in situ hybridization. We found a considerable concordance between HPV16 ( ‫؍‬ 0.661) and HPV18 ( ‫؍‬ 0.781) status as measured by real-time PCR and conventional PCR, indicating similar sensitivities. We recognized an inhibitory effect of formalin fixation and paraffin embedding on the evaluation of real-time PCR quantification.Formalin-fixed, paraffin-embedded (FFPE) tissues retained in pathology archives are an important resource for molecular pathology studies and for diagnostic applications. The use of in situ hybridization (ISH) and PCR assays have both been reported for DNA analysis in formalin-fixed archival tissues (6,7,25,40,42,48). Both assays have the advantage that only small amounts of tissue are required, and both tolerate the degradation of target nucleic acids due to the formalin fixation and paraffin-embedding procedures. Each assay per se has its own advantages and disadvantages.For a pathologist, the retention of morphology and the histological context of a tumor is very important. Especially in the case of cervical carcinoma, the phenomenon of koilocytosis indicates an infection with human papillomavirus (HPV) (4) that can only be detected by microscopic analysis of tissue sections. Moreover, episomal and integrated viral DNA can only be differentiated by ISH due to the staining pattern (8). With the use of chromogenic tyramide-signal-amplified ISH (CISH) it is even possible to detect and localize single or very few HPV copies within infected nuclei (15,36,49). However, this technique is rather cost-intensive and quite involved for routine applications.Conventional PCR is held to be the most sensitive detection method available (9,16,20,27,37,41). Although this is probably true, it has some limitations, as does ISH, in that it cannot quantify viral load in a prognostic-diagnostic significant manner. This restriction can be circumvented by the use o...

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