HPV testing and Pap test: role for a combined approach in a non-screened population.

The aim of the present study was to test the polymerase chain reaction (PCR) as a tool to identify human papillomavirus (HPV) in routine cytological samples scraped from the uterine cervix. Moreover, attention has been focused on the correlation between HPV types and early intraepithelial lesions. The study involved 586 women who had undergone conventional Pap test. Analysis of HPV infection was performed by PCR and HPV typing by dot blot. In a group of 78 cases histologically diagnosed as high-grade squamous intraepithelial lesions (HSILs), the cytological diagnosis was correct in 92.3% and the HPV test was positive in 89.8% of cases; combined positivity at Pap and/or HPV tests raised this figure to 99.0%. In a group of 67 cases histologically diagnosed as low-grade squamous intraepithelial lesions (LSILs), the cytological diagnosis was correct in 73.1% and the PCR-based HPV test was positive in 64.2%; combined positivity at Pap and/or HPV tests raised this figure to 91.0%. This study confirms the limitations of screening programs based on Pap test only. Our results suggest, in fact, that adding the HPV test to primary screening could increase the yield of preinvasive cervical lesions.

mRNA markers of breast cancer nodal metastases: comparison between mammaglobin and carcinoembryonic antigen in 248 patients.

Histological detection of axillary lymph node metastases is still the most valuable prognostic parameter for breast cancer, but about 30% of node-negative patients relapse within five years, suggesting that current methods are inadequate for identifying metastatic disease. More sensitive, PCR-based methods for the detection of metastatic cells are now available, enabling the amplification of cancer cell-specific mRNA messages by the RT-PCR assay. An ideal tumour marker, consistently expressed in tumour samples and not at all in normal lymph nodes, remains to be identified. The present study first investigated the expression of seven mRNA markers, CEA, CK19, c-Met, mammaglobin, MUC-1, beta1-->GalNAc-T and p97, selected on the basis of their previously reported specificity for breast cancer cells. Eighteen lymph nodes were examined from patients without tumours. Only mammaglobin mRNA and CEA mRNA were not expressed in normal nodes. All of the other markers showed a band of expression in 17%-55% of cases, indicating that they are not breast cancer-specific. CEA mRNA and mammaglobin mRNA expression could be detected in 15/20 (75%) and 19/20 (95%) primary breast carcinomas, respectively. The expression of mammaglobin mRNA and CEA mRNA was then compared in axillary lymph nodes from 248 consecutive breast cancer patients, 89 with histologically documented lymph node metastasis and 159 without histological evidence of metastatic disease. Ninety-seven per cent of the patients with histologically involved nodes showed expression of mammaglobin mRNA, whereas CEA mRNA was expressed in 79% of these cases. In the group of patients with histologically negative lymph nodes, 46 (29%) and 32 (20%) were found to be positive for mammaglobin and CEA expression, respectively, indicating the presence of metastases not detected by routine histological examination of one lymph node section. These results show that both mammaglobin RT-PCR and CEA RT-PCR are useful tools for the detection of breast cancer metastases in axillary lymph nodes. The detection sensitivity of the mammaglobin RT-PCR is far superior to that of the CEA RT-PCR, allowing the diagnosis of occult metastases in nearly one-third of cases.

Reduced expression of INT-6/eIF3-p48 in human tumors.

The int-6 gene, originally identified as a common integration site for the mouse mammary tumor virus (MMTV) in mouse mammary tumors, encodes the p48 component of the eukaryotic translation initiation factor-3 (eIF3-p48). Int-6/eIF3-p48 is expressed in all adult tissues which have been tested and early in embryonic development. Int-6/eIF3-p48 has been highly conserved throughout evolution and the deduced amino acid sequence of the human gene product is identical to the mouse protein. Viral insertions at the Int-6/eIF3-p48 locus in mouse mammary tumors result in production of chimeric Int-6/eIF3-p48/MMTV products that may act as dominant negative oncoproteins. Int-6/eIF3-p48 has also been identified as a human protein that binds to the human T-cell leukemia virus type I Tax oncoprotein. The role of Int-6/eIF3-p48 in human carcinogenesis is unknown at the present time. In this study we have examined Int-6/eIF3-p48 gene status and expression in two of the most common forms of cancer in humans, breast and lung tumors. Sixty-two breast carcinomas and 78 non-small cell lung carcinomas (NSCLC) were investigated. LOH at the Int-6/eIF3-p48 locus was observed in 5 (21%) of 24 informative breast tumors and 10 (29%) of 34 informative lung tumors. A reduced expression of Int-6/eIF3-p48 was seen in 23 (37%) of breast cancer samples and 24 (31%) of NSCLC samples. An association between Int-6/eIF3-p48 expression and LOH at the Int-6/eIF3-p48 locus was observed. Int-6/eIF3-p48 expression was not related to commonly used pathological parameters in breast cancer patients, while in NSCLC patients int-6/eIF3-p48 expression was mainly seen in adenocarcinomas (P<0.0001). In conclusion, our data show for the first time a decreased expression of Int-6/eIF3-p48 in a consistent portion of human breast and lung carcinomas, frequently associated with LOH at the Int-6/eIF3-p48 locus. Additional studies on larger series of tumor specimens with long-term follow-up are needed to determine whether Int-6/eIF3-p48 expression may represent a new prognostic or predictive marker.

Microsatellite alterations and K-ras, TGFbetaRII, IGFRII and bax mutations in sporadic cancers of the gastrointestinal tract.

DNA was analyzed from 57 sporadic gastrointestinal tumors (34 pancreatic cancers, 23 colon tumors) and cognate normal tissues to verify whether mutations at coding sequences were associated with microsatellite instability (MSI). Genomic instability was present in 41% (14/34) of pancreatic samples and in 26% (6/23) of colon cancers previously tested by six microsatellite markers. The tumors included 37 cases showing no MSI; 15 cases with MSI at only 1 locus and 5 cases with MSI at 2 or more loci. All the samples were screened for mutations in genes containing repeated tracts in their coding sequences (TGFbetaRII, IGFRII and bax) and in codon 12 of the K-ras oncogene. Furthermore, loss of heterozygosity (LOH) at NM23.H1 locus was tested, 17/34 (50%) pancreatic tumors and 6/23 (26%) colon cancers showed mutations in codon 12 of K-ras; allelic loss of NM23. H1 locus was found in 6/18 (33%) informative colon tumors and in no pancreatic cancers. The TGFbetaRII, IGFRII and bax genes were altered in 3 (13%), 1 (4%) and 3 (13%) out of 23 colon tumors respectively, but no mutation was detected in pancreatic cancers. Mutations in the repeated nucleotide stretches within the coding sequences of TGFbetaRII, IGFRII and bax genes were found only in colon tumors with a high unstable phenotype (more than 3 microsatellite loci altered).

Lung tumours from non-smoking subjects: A p53-related genetic instability in a subset of cases.

Tumours developed in non-smoking patients represent about 10% of all lung neoplasms and show peculiar morphologic and genetic features. In a previous study, we found a constant association between p53 gene alterations and loss of heterozygosity (LOH) at the FHIT locus in a subset of non-smoking tumours (7 cases out of 35 analyzed), so we hypothesized that a genomic instability associated with p53 mutations could be the cause of FHIT LOH in these neoplasms. To test this hypothesis, in the same panel of tumours, we investigated the presence of LOH at 7 other microsatellite loci located on different chromosomes. Interestingly we found that all of the tumours with p53 alterations and LOH at the FHIT locus showed loss of heterozygosity at all of the informative tested loci. This association was statistically significant (p=0.0001). Our data indicate the presence of a generalized genomic instability in this subset of lung tumours. Since p53 alterations were mostly G:C --> A:T transitions and frameshift deletions, we are tempted to hypothesize that the genomic instability observed in non-smoking patients could be caused by particular p53 alterations. In fact, other kind of p53 mutations (G:C --> T:A transversions), frequently found in a series of 35 tumours of smokers used as control, were not associated with LOH at microsatellites loci. However, we cannot exclude that p53 alterations are a consequence and not the cause of the genomic instability. In this case, we have to admit that a gene(s), upstream of p53, is implicated in genome destabilisation in a subset of lung adenocarcinomas developed in non-smoking patients.

Telomerase activity as a prognostic indicator in stage I non-small cell lung cancer.

Patients with stage I non-small cell lung cancer (NSCLC) are typically treated with surgical resection alone. However, about one-third of such patients develop disease recurrence and die within 5 years after complete resection. The ability to predict recurrence could represent an important contribution to treatment planning. This study evaluates the presence of telomerase activity in tumor cells as a predictor of disease recurrence and cancer-related death after operation for stage I NSCLC patients. The activity of the telomerase enzyme was investigated by telomeric repeat amplification protocol (TRAP) in tumors and matching normal lung tissue samples obtained from 107 consecutive operable patients with pathological stage I NSCLC. Telomerase activity was detected in 66 (62%) of the 107 tumors examined and in none of the corresponding adjacent noncancerous lung tissue samples. Correlation with pathological parameters showed that telomerase activity was associated with histopathological grade (P = 0.0135) but not with tumor size or histological type. Univariate survival curves, estimated using the method of Kaplan and Meier, defined a significant association between telomerase activity and both disease-free survival (P = 0.0115) and overall survival (P = 0.0129). In multivariate analyses, performed by Cox's proportional hazards regression models, the presence of telomerase activity was the only strong predictor of disease-free survival (P = 0.0173) and overall survival (P = 0.0187). Our data indicate that telomerase activity can be an important prognostic factor that should be considered in future prospective trials of adjuvant therapy for high-risk stage I NSCLC patients.

Genetic analysis of lung tumours of non-smoking subjects: p53 gene mutations are constantly associated with loss of heterozygosity at the FHIT locus.

Lung cancer is strictly associated with tobacco smoking. Tumours developed in non-smoking subjects account for less than 10% of all lung cancers and show peculiar histopathological features, being prevalently adenocarcinomas. A number of genetic data suggest that their biological behaviour may be different from that of lung tumours caused by smoking, however the number of cases investigated to date is too low to draw definitive conclusions. We have examined the status of p53 and K-ras genes and the presence of loss of heterozygosity (LOH) at the FHIT locus in a series of 35 lung adenocarcinomas that developed in subjects who had never smoked. Results were compared with those obtained in a series of 35 lung adenocarcinomas from heavy-smoking subjects. In the group of non-smoking subjects p53 mutations and LOH at the FHIT locus were present in seven (20%) cases, and the two alterations were constantly associated (P < 0.0001), whereas they were not related in the series of carcinomas caused by smoking. In tumours developed in heavy-smoking subjects, the frequency of LOH at the FHIT locus was significantly higher (P = 0.006) than in tumours from non-smoking subjects. The frequency of p53 mutations in adenocarcinomas caused by smoking was not different from that seen in non-smoking subjects. However, in the group of smoking subjects we observed mostly G:C --> T:A transversions, whereas frameshift mutations and G:C --> A:T transitions were more frequently found in tumours from non-smoking subjects. No point mutations of the K-ras gene at codon 12 were seen in subjects who had never smoked, whereas they were present (mostly G:C --> T:A transversions) in 34% of tumours caused by smoking (P = 0.002). Our data suggest that lung adenocarcinomas developed in subjects who had never smoked represent a distinct biological entity involving a co-alteration of the p53 gene and the FHIT locus in 20% of cases.

FHIT and p53 gene abnormalities in bronchioloalveolar carcinomas. Correlations with clinicopathological data and K-ras mutations.

Bronchioloalveolar carcinoma (BAC) is a particular type of adenocarcinoma of the lung which accounts for up to 9 per cent of pulmonary malignancies. The aetiology and pathogenesis of this unique neoplastic disease are still unclear. Three histological subtypes of BAC have been recognized: mucinous, non-mucinous, and sclerosing. Of these, mucinous and sclerosing BAC have a worse prognosis than non-mucinous tumours. The different morphological patterns and clinical outcomes of the subtypes of BAC suggest differences in their biological behaviour. Previous reports have shown that the mucinous form of BAC is characterized by constant mutations at codon 12 of the K-ras gene, whereas the other two histotypes show a frequency of K-ras mutations which is not different from that observed in conventional lung adenocarcinomas. The present study of a series of 51 BACs, previously investigated for K-ras gene mutations, has evaluated the status of two other genes, p53 and FHIT, known to be frequently altered in non-small cell lung cancer. Loss of heterozygosity at microsatellite-containing loci located within the FHIT gene was observed in 22 (43 per cent) BACs. The distribution of FHIT gene abnormalities was not statistically different in the three histological subtypes. p53 mutations were present in 13 (32 per cent) non-mucinous/sclerosing BACs, while no mutations were seen in mucinous tumours (P = 0.039). Correlations with clinicopathological parameters showed that p53 mutations in BACs are associated with more aggressive tumours. No correlations were observed between FHIT or K-ras gene abnormalities and clinicopathological data. In conclusion, these results indicate that FHIT alterations are frequently involved in BAC tumourigenesis and that genetic changes in the p53 and K-ras genes can distinguish between different histotypes of BAC.

Evaluation of FHIT gene alterations in ovarian cancer.

The FHIT gene, recently cloned and mapped on chromosome 3p14.2, has frequently been found to be abnormal in several established cancer cell lines and primary tumours. As alterations of chromosome 3p are common events in ovarian cancers with breakpoint sites at 3p14.2, we decided to investigate the role of FHIT in human ovarian tumorigenesis. Fifty-four primary ovarian carcinomas were studied by reverse transcription of FHIT mRNA followed by polymerase chain reaction (PCR) amplification and sequencing of products. The same tumours and matched normal tissues were also investigated for loss of heterozygosity using three microsatellite markers located inside the gene. We found an abnormal transcript of the FHIT gene in two cases (4%) and allelic losses in eight cases (15%). Twelve (22%) of the 54 tumours investigated belonged to young patients with a family history of breast/ovarian cancer. In none of these cases was the FHITgene found to be altered. Our results indicate that FHITplays a role in a small proportion of ovarian carcinomas.

Enriched SSCP: a highly sensitive method for the detection of unknown mutations. Application to the molecular diagnosis of lung cancer in sputum samples.

Detection of gene mutations by sensitive polymerase chain reaction (PCR)-based methods can allow to identify occult neoplastic cells in a great excess of nonmalignant cells. These molecular approaches have an enormous potential in terms of early diagnosis, detection of occult micrometastases of solid tumors, and minimal residual disease in patients with hematopoietic malignancies. Currently, the applications of such methods are limited, mainly because the high sensitivity required for the identification of rare mutated alleles can be achieved only in cases in which mutations occur in few specific codons of a gene or when the mutation is already known. No methods are available by which few alleles with unknown mutations in tumor genes can be recognized in a great excess of wild-type alleles. We have developed an extremely sensitive method, termed enriched single-strand conformational polymorphism (E-SSCP), which permits detection of a rare alleles with unknown mutations. The method is based on the observation that after a conventional SSCP analysis the vast majority of mutated bands migrate close to the wild-type bands. The area of the gel having the highest chance to hold mutated alleles is physically isolated and is used as substrate for a second round of SSCP. Serially diluted DNA samples containing gene mutations demonstrated detection of 1 mutant/10(6) normal alleles. The E-SSCP assay was first applied to six sputum samples of patients affected by lung cancers with known p53 mutations showing in sputa the same mutations observed in tumors. The technique was then applied to eight cytologically negative sputum samples obtained from patients who later developed a clinically manifested lung carcinoma. In three cases, harboring a p53 mutation in tumor tissue, the E-SSCP analysis allowed the detection of the mutations in sputa months before clinical diagnosis. In conclusion, we have presented a general, highly sensitive technique for the detection of unknown mutations that may have several potential applications and may hold considerable promise for the early detection and study of cancer.

Alterations of P16 (MTS1) in node-positive non-small cell lung carcinomas.

The status of the P16 gene was investigated by Southern blot, polymerase chain reaction-single strand conformational polymorphism (PCR-SSCP), and DNA sequencing analyses in 30 primary resected non-small cell lung carcinomas (NSCLCs) with metastatic involvement of thoracic lymph nodes and 33 NSCLCs without node metastases. Direct sequencing of tumour DNA samples scored positive by PCR-SSCP showed five somatic mutations of the P16 gene: four nonsense and one frameshift. The Southern blot analysis revealed the presence of a homozygous deletion of the P16 locus in one tumour. All of the six NSCLCs with somatic aberrations of the P16 gene belonged to the series of tumours with metastatic diffusion to thoracic lymph nodes. In each of these six cases, the genetic aberration was seen in both the primary tumour and the node metastasis. No P16 alteration was found in tumours without metastatic lymph nodes. This difference was statistically significant (P = 0.02). No correlation was present between P16 alterations and other clinicopathological parameters including age of patients, tumour size, histological type, and grade. In three tumours with genetic aberration of P16, there was a concomitant alteration of the p53 gene. Our results indicate that the P16 gene is infrequently mutated (10 per cent of the cases examined) in primary resected NSCLC. However, since P16 mutations were found only in metastatic tumours, they may be important events in late phases of tumour progression and could represent useful markers of tumour aggressiveness in NSCLC.

Bronchioloalveolar lung carcinomas: K-ras mutations are constant events in the mucinous subtype.

Bronchioloalveolar carcinoma (BAC) is a form of peripheral lung adenocarcinoma growing as a single layer of malignant cells along the walls of terminal airways. The existence of BAC as a separate clinico-pathological entity has been a matter of controversy, mainly because its histogenesis is uncertain and it is not easily distinguishable from conventional lung adenocarcinoma (CLA). Three subtypes of BAC have been described using histological and cytological criteria: mucinous, non-mucinous, and sclerosing. The clinical behaviour of BAC appears to be dependent on the histological subtype. The different morphological patterns and clinical outcome of the subtypes of BAC suggest that their biological behaviour may be different from one another and from CLA. This study has investigated 58 BACs (10 mucinous, 40 non-mucinous, and 8 sclerosing) and 50 control CLAs for mutations at codon 12 of the K-ras oncogene. Twenty-one (36 per cent) BACs and 13 (26 per cent) CLAs showed K-ras mutations. A clear association (P < 0.0001) between K-ras mutations and the mucinous type of BAC was observed: all 10 mucinous tumours examined were scored positive for mutations in the K-ras gene, while only 9 (23 per cent) of the 40 non-mucinous and 2 (25 per cent) of the 8 sclerosing BACs were found to be positive. The frequency of ras mutations in non-mucinous BAC, sclerosing BAC, and CLA was not statistically different. Our data indicate that BACs are a heterogeneous group of lung tumours and that the mucinous form might represent a biological entity separate from both the other two BAC types and CLA.

p21 RNA and protein expression in non-small cell lung carcinomas: evidence of p53-independent expression and association with tumoral differentiation.

p21, the product of the WAF1/CIP1/SDI1/mda-6 gene, is an inhibitor of cyclin-dependent kinases. In cell cultures p21 is induced by p53-dependent and p53-independent pathways by DNA damage and induction of differentiation. We investigated p21 RNA and immunohistochemical expression in 43 non-small cell lung carcinomas and corresponding normal lung samples previously investigated for p53 and WAF1 gene status and p53 protein expression. p21 RNA and protein expression in normal and neoplastic tissues were strictly associated (p-0.0001). In normal tissue p21 RNA was expressed at low levels and p21 immunoreactivity was seen in scattered differentiated bronchial, alveolar and stromal cells. In the majority of neoplasms p21 protein and RNA were expressed at higher levels than in the corresponding normal tissues: p21 overexpression was seen in 27 (63%) and 28 (65%) cases respectively. p21 was expressed independently from p53 gene/protein alterations. p21 overexpression was more frequent in well differentiated tumors (P=0.01 and P=0.022 for RNA and protein respectively), and p21 immunoreactivity was usually seen in foci of more pronounced differentiation. We conclude that p21 expression is related to tumor differentiation, and that p53-independent p21 expression is a common feature of in vivo neoplasms.

Absence of somatic mutations in the coding region of the waf1/cip1 gene in human breast, lung and ovarian carcinomas - a polymorphism at codon-31.

Seventy-four invasive ductal, breast carcinomas, 73 non-small cell lung carcinomas and 36 ovarian adenocarcinomas, obtained from 183 unrelated patients, were investigated for mutations in the WAF1/CIP1 coding sequence by reverse transcriptase-polymerase chain reaction-single strand conformation polymorphism analysis. No somatic mutations were present in the WAF1/CIP1 open reading frame (ORF) in tumor samples. A polymorphism at codon 31 was observed in 16 (8.7%) cancer patients and in 9 (8.8%) of 102 unrelated normal individuals. The polymorphic allele changes the codon 31 AGC to AGA, thus implying an aminoacid substitution from serine to arginine, and creates a Hga-1 restriction site which might be useful for deletion studies. The polymorphism was present in the heterozygous state, except for the case of a 70-year-old male lung cancer patient who was homozygous: Our results indicate that the coding region of WAF1/CIP1 is not a frequent target for somatic mutations in breast, lung and ovarian cancer.