PubMed Health⌕ Search

Biomedical subjects

C Romei

Publications and source records attributed to C Romei.

At least 19 recordsLinked to original sources
PubMed2006

Correlation between B-RAFV600E mutation and clinico-pathologic parameters in papillary thyroid carcinoma: data from a multicentric Italian study and review of the literature.

Recently, a somatic point mutation of the B-RAF gene (V600E) has been identified as the most common genetic event in papillary thyroid carcinoma (PTC), with a prevalence variable among different series. Since discordant data on the clinico-pathologic features of B-RAF mutated PTC are present in the literature, the aim of the present co-operative study was to establish the prevalence of this genetic alteration and to perform a genotype-phenotype correlation in a large cohort of patients with PTC. To this purpose, a series of 260 sporadic PTCs with different histological variants were included in the study. The mutational analysis of the B-RAF gene was performed either by RT-PCR followed by single-stranded conformational polymorphism or by PCR and direct sequencing. Statistical analyses were obtained by means of chi2/Fisher's exact test and t-test. Overall, a heterozygous T > A transversion at nucleotide 1799 (V600E) was found in 99 out of 260 PTCs (38%). According to the histological type of the tumor, the B-RAF (V600E) mutation was present in 48.3% of cases of classic PTCs (85 out of 176), in 17.6% (nine out of 51) of follicular variants of PTCs, in 21.7% (five out of 23) in other PTC variants and in none of the ten poorly differentiated tumors. B-RAF (V600E) was significantly associated with the classic variant of PTC (P = 0.0001) and with an older age at diagnosis (P = 0.01). No statistically significant correlation was found among the presence of B-RAF (V600E) and gender, tumor node metastasis (TNM), multicentricity of the tumor, stage at diagnosis and outcome. In conclusion, the present study reports the prevalence of B-RAF (V600E) (38%) in the largest series of sporadic PTCs, including 260 cases from three different Italian referring centers. This prevalence is similar to that calculated by pooling together all data previously reported, 39.6% (759 out of 1914 cases), thus indicating that the prevalence of this genetic event lies around 38-40%. Furthermore, B-RAF (V600E) was confirmed to be associated with the papillary growth pattern, but not with poorer differentiated PTC variants. A significant association of B-RAF mutation was also found with an older age at diagnosis, the mutation being very rare in childhood and adolescent PTCs. Finally, no correlation was found with a poorer prognosis and a worse outcome after a median follow-up of 72 months.

Adolescent↗
PubMed2004

A new germline RET mutation apparently devoid of transforming activity serendipitously discovered in a patient with atrophic autoimmune thyroiditis and primary ovarian failure.

Gain-of-function RET mutations are responsible for multiple endocrine neoplasia syndromes (MEN) 2A and 2B and familial medullary thyroid carcinoma (FMTC), whereas loss-of-function mutations are found in Hirschsprung disease. We report a new RET point mutation [R694Q (CGG-->CAG)], serendipitously found in a 23-yr-old woman with hypothyroidism due to atrophic Hashimoto's thyroiditis and primary ovarian failure, without altered calcitonin secretion. Familial history and clinical and biochemical evaluation of first-degree relatives were negative for FMTC, MEN 2A and 2B, and Hirschsprung disease. Genetic analysis showed that the mutation was inherited from the mother, who was submitted 2 yr before to thyroidectomy for goitrous Hashimoto's thyroiditis. Histological revision and immunohistochemical studies documented normal C cell number and morphology. We cloned the mutation in an expression vector encoding a full-length RET protein. The construct was transiently expressed in 293T cells in parallel with a wild-type RET and a C634R MEN 2A-associated RET mutant. Proteins were harvested from transfected cells, and tyrosine phosphorylation levels were assayed. The mutation did not exert significant potentiating effects on RET kinase. A focus assay was also performed on NIH3T3 fibroblasts; the mutant did not exert significant transforming activity. In conclusion, a new RET mutation was found in two subjects without any evidence of MEN and FMTC. In keeping with clinical data, transfection studies confirmed lack of activating activity. This serendipitous discovery, apparently devoid of oncogenic potential, underscores the problems that may be encountered in genomic studies on RET.

Adult↗
PubMed2001

RET/PTC rearrangements in thyroid nodules: studies in irradiated and not irradiated, malignant and benign thyroid lesions in children and adults.

Rearrangements of the RET proto-oncogene may occur in both naturally occurring and radiation-induced papillary thyroid carcinomas. Conflicting results on the frequency and type of RET/PTC rearrangements have been reported in relation to age, radiation exposure, and histological tumor variant. We designed the present study to evaluate in a single laboratory, using the same methodologies, the pattern of RET/PTC activation in thyroid tumors from different groups of patients (exposed or not exposed to radiation, children or adults, with benign or malignant tumors) in relationship to the above mentioned variables. We studied 154 patients with benign nodules (n = 65) or papillary thyroid cancer (n = 89). In the last group, 25 were Belarus children exposed to the post-Chernobyl radioactive fallout, 17 were Italian adults exposed to external radiotherapy for benign diseases, and 47 were Italian subjects (25 children and 22 adults) with no history of radiation exposure. Among patients with benign thyroid nodules, 21 were Belarus subjects (18 children and 3 adults) exposed to the post-Chernobyl radioactive fallout, 8 were Italian adults exposed to external radiation on the head and neck, and 36 were Italian adults with naturally occurring benign nodules. The overall frequency of RET/PTC rearrangements in papillary thyroid cancer was 55%. The highest frequency was found in post-Chernobyl children and was significantly higher (P = 0.02) than that found in Italian children not exposed to radiation, but not significantly higher than that found in adults exposed to external radiation. No difference of RET/PTC rearrangements was found between samples from irradiated (external x-ray) or not irradiated adult patients, as well as between children and adults with naturally occurring, not irradiated, thyroid cancer. When analyzing the type of RET/PTC rearrangement (RET/PTC1 or RET/PTC3), no major difference was apparent. In addition, eight cases with an unknown RET/PTC rearrangement and three cases with the concomitant expression of RET/PTC1 and RET/PTC3 were found. No significant correlation was observed between the frequency and/or the type of RET/PTC rearrangement and clinical-epidemiological features of the patients such as age at diagnosis, age at exposure, histological variant, gender and tumor-node-metastasis (TNM) categories. RET/PTC rearrangements were also found in 52.4% of post-Chernobyl benign nodules, in 37.5% of benign nodules exposed to external radiation and in 13.9% of naturally occurring nodules (P = 0.005, between benign post-Chernobyl nodules and naturally occurring nodules). The relative frequency of RET/PTC1 and RET/PTC3 in rearranged benign tumors showed no major difference. In conclusion, our results indicate that the presence of RET/PTC rearrangements in thyroid tumors is not restricted to the malignant phenotype, is not higher in radiation-induced tumors compared with those naturally occurring, is not different after exposure to radioiodine or external radiation, and is not dependent from young age. Other factors, probably influenced by ethnic or genetic background, may act independently from or in cooperation with radiation, to trigger the DNA damage leading to RET proto-oncogene activation.

Adolescent↗
PubMed2000

RET proto-oncogene mutations in thyroid carcinomas: clinical relevance.

Different forms of RET mutations are found in papillary and medullary thyroid carcinomas. Rearrangements with other genes (RET/PTC oncogene) play a causative role in a significant proportion of papillary thyroid carcinomas. In this case, several factors influence the frequency and the type of RET/PTC, such as exposure to radiation, age and histological variant of the papillary tumor. On the other hand, the presence of the mutation does not seem to influence the biological behavior of the tumor or its response to conventional treatment modalities. In the setting of medullary thyroid cancer, germline RET point-mutations are implicated in the pathogenesis of virtually all hereditary forms and somatic point-mutations in nearly half of the sporadic forms. The clinical impact of this finding is that family members at-risk of hereditary MTC may be screened by genetic analysis, to distinguish those carrying or not-carrying the mutation. The last can be reassured on their status and relieved from further follow-up. Those with the mutation may be treated at a pre-clinical stage of the disease or even before the disease is started. The present review is focused on the clinical implication of RET gene mutations in thyroid cancer patients.

Carcinoma, Medullary↗
PubMed2000

New breakpoints in both the H4 and RET genes create a variant of PTC-1 in a post-Chernobyl papillary thyroid carcinoma.

Two main types of RET/PTC oncogene, named RET/PTC-1 and 3, occur in papillary thyroid carcinomas especially in those from Belarus children after the Chernobyl nuclear accident. Several variants of RET/PTC-3 have also been found, having different break points with respect to the classical RET/PTC-3. To our knowledge, no variant of RET/PTC-1 has been described up to now. We found a post-Chernobyl papillary thyroid carcinoma with an RET/PTC-1 rearrangement characterized by a transcript longer than expected. Sequence analysis of the PCR product obtained after RT-PCR revealed new fusion points between H4 and RET genes. The genomic sequence showed new breakpoints in both H4 intronic and in RET exonic regions. The RET gene breakpoint occurred within exon 11, at variance with the classical form of RET/PTC-1, in which it is in intron 11. As a consequence of this new fusion point, the transcript included 132 nucleotides of exon 11, coding for 44 amino acids of RET protein. Regarding the H4 gene, the classical breakpoint is in the first intron and the cDNA contains a fragment of 339 nucleotides. In our case the cDNA had a longer fragment of H4 involving a total of 1266 nucleotides. Sequencing of genomic DNA revealed a rearrangement breakpoint at position 886 of a new H4 intron located downstream of the 1266 coding region. Furthermore, as a consequence of the activation of a cryptic splicing site, 132 nucleotides of this intron were spliced between the H4 and RET genes. Sequence analysis of the new chimera showed that the original frames of H4 and RET were joint with the intronic sequence without disruption of the open reading frame (ORF). Moreover, the genomic DNA of this case showed transforming activity in the DNA-mediated transfection assay using NIH-3T3 cells. In conclusion, we describe here the first variant of RET/PTC-1 oncogene, which we have termed 'long'-PTC-1, characterized by new breakpoints of both genes involved in the rearrangement and having transforming activity. Similar to previously reported PTC-3 variants, long-PTC-1 has been found in a post-Chernobyl papillary thyroid carcinoma confirming that RET/PTC rearrangements other than the classical forms (RET/PTC-1 and -3) are specifically associated with radiation-induced papillary thyroid cancer.

Carcinoma, Papillary↗
PubMed1998

Simian virus 40-like DNA sequences in human papillary thyroid carcinomas.

Sequences of the SV40 virus, a virus of Asian macaques, have been found in human tumors, such as pleural mesotheliomas, ependimomas and choroid plexus tumors. Transgenic mice carrying the SV40 large T gene under the transcriptional control of the thyroglobulin gene promoter, develop thyroid dedifferentiation and follicular thyroid cell proliferation, leading to thyroid hyperplasia and adenocarcinomas. On these bases we investigated the presence of SV40 DNA sequences in 69 samples of papillary thyroid carcinomas (PTC) and in other thyroid and non-thyroid carcinomas, as well as in benign thyroid diseases. By Southern blot and PCR amplification followed by sequence analysis, we found the presence of SV40-related sequences integrated in the tumoral DNA of three cases of PTC. At least the 203 bp fragment of the aminoterminus of large T antigen, the 294 bp fragment of the VP1 gene and the 483 bp entire regulatory region were present in the tumoral DNA of these patients. SV40 sequences were not found in tissues other than PTC. Our results demonstrate that, in addition to previous findings in mesotheliomas and brain tumors, SV40 is somehow linked to papillary thyroid carcinoma. Although our data do not demonstrate a causative role in the development of PTC, this possibility must be considered and requires further studies.

Adolescent↗
PubMed1997

Somatic in frame deletions not involving juxtamembranous cysteine residues strongly activate the RET proto-oncogene.

Somatic RET mutations have been identified in a variable proportion (about 30-70%) of sporadic Medullary Thyroid Carcinoma (MTC) cases. They are represented by the Met918Thr substitution (exon 16) typical of Multiple Endocrine Neoplasia type 2B (MEN2B) and, to a lesser extent, by nucleotide changes occurring at one of five critical cysteine residues (exons 10 and 11) typical of MEN type 2A (MEN2A). An in vitro transforming activity has already been demonstrated for these mutations. A few different MTC somatic mutations have been reported so far whose biological activity has still to be tested. In this paper we report the identification, in two MTC tumor samples, of two interstitial deletions of 48 bp and 6 bp occurred in exons 10 and 11 respectively. Both were somatic heterozygous in frame mutations, not involving any cysteine residue. Moreover, the expression of a full length RET cDNA carrying one of the two deletions demonstrated a strong transforming capacity in NIH3T3 cells.

3T3 Cells↗
PubMed1997

Polyclonal origin of medullary carcinoma of the thyroid in multiple endocrine neoplasia type 2.

Multiple endocrine neoplasia type 2 (MEN 2) is a dominantly inherited cancer syndrome characterized by medullary thyroid carcinoma (MTC) and other tumors. Since MTC can also occur in a sporadic form and as familial medullary thyroid carcinoma, this neoplasm offers a unique opportunity to investigate the difference of origin, if any, between the sporadic and the hereditary forms of a tumor. While sporadic malignancies have usually been found to result from a mutational event occurring at the single-cell level and are therefore monoclonal, studies on hereditary neoplasms have been scarce and often produced conflicting results. In order to determine the clonal origin of sporadic MTCs and of those occurring in MEN 2 syndromes we used a clonality assay based on a polymorphic trinucleotide repeat of the X-linked human androgen-receptor gene. We found that 10 out of 11 MTCs expressed a polyclonal pattern of X inactivation, including a significant percentage of the cases clinically defined as sporadic.

Adolescent↗
PubMed1997

Post-Chernobyl thyroid carcinoma in Belarus children and adolescents: comparison with naturally occurring thyroid carcinoma in Italy and France.

After the Chernobyl nuclear accident (April 26, 1986), childhood thyroid carcinoma had a great increase in Belarus and Ukraine, as a consequence of the exposure to iodine radioactive fallout. The epidemiological and clinical features of the disease were studied in 472 patients less than 21 yr old at diagnosis, with differentiated thyroid carcinoma, representing 97.7% of all thyroid carcinomas diagnosed in Belarus between May, 1986, and December, 1995. The results were compared with those of 369 subjects of the same age group, with naturally occurring thyroid carcinoma, observed in Italy and France. Between 1986 and 1989, the number of thyroid cancer cases per year ranged from 3-8 and increased to 31 in 1990, to 66 in 1991, to 72 in 1992, to 93 in 1993, to 96 in 1994, and to 90 in 1995. The age at diagnosis was 14 yr or less in 78.8% (children group) and more than 14, but less than 21, yr in the remaining subjects (adolescents group). Mean (+/- SD) age at the time of the accident was 4.4 +/- 3.4 yr (3.2 +/- 2.3 in children and 8.9 +/- 2.7 in adolescents), the majority of the patients (62.9%) being 5 yr old or less. The time interval between the accident and the diagnosis (latency period) decreased progressively from 7.5 +/- 1.6 yr in children 0-2 yr old at the time of the accident to 6.0 +/- 1.6 yr in those 9-11 yr old. Since 1993, the yearly distribution of new cases showed a decrease in the subjects 9 yr old or more at the time of the accident but not in those 5 yr old or less. This could not be accounted for by a shift of exposed subjects to an age group at diagnosis not included in this study, because only subjects less than 12 yr of age at the time of the accident were considered in this analysis. Mean age at diagnosis in Belarus patients was 11.3 +/- 3.1 yr (10.1 +/- 2.3 in children and 15.7 +/- 1.4 in adolescents), whereas, among patients with naturally-occurring thyroid carcinomas from Italy and France, the majority of cases were diagnosed after 14 yr of age (mean age at diagnosis: 14.6 +/- 4.2 yr). The female-to-male ratio was significantly higher in Italy and France (2.5/1), compared with the ratio of patients from Belarus (1.6/1). Most of the tumors were papillary in both series, but a relatively high proportion of follicular carcinomas (P = 0.0001) was found in Italy/France (15.2%), as opposed to 5.3% in Belarus. Extrathyroidal extension and lymph node metastases were more frequent in Belarus (49.1%, P = 0.0001; and 64.6%, P = 0.002, respectively) with respect to Italy/France (24.9% and 53.9%, respectively). Thyroid lymphocytic infiltration and circulating antithyroperoxidase antibody were more frequent in Belarus patients. Our analysis of Belarus thyroid cancer patients less than 21 yr old showed that the post-Chernobyl increase in thyroid carcinomas involved both children and, to a much lesser extent, adolescents. Subjects 5 yr old or less at the time of the accident accounted for the majority of the patients. No evidence of a decrease in the number of new cases was observed in this age group, as opposed to older subjects. These data support the concept that subjects who were younger at the time of radiation exposure had, and continue to have, a greater risk of developing thyroid carcinoma and strongly suggest that this age group should be carefully monitored in the future. When compared with naturally occurring thyroid carcinoma of the same age group observed in Italy and France, the post-Chernobyl Belarus thyroid carcinomas affected younger subjects, were less influenced by gender, were virtually always papillary, had a greater aggressiveness at presentation, and were more frequently associated with thyroid autoimmunity.

Adenocarcinoma, Follicular↗
PubMed1996

The relationship between specific RET proto-oncogene mutations and disease phenotype in multiple endocrine neoplasia type 2. International RET mutation consortium analysis.

OBJECTIVE: Multiple endocrine neoplasia type 2 (MEN 2) is an autosomal dominant disorder. The 3 recognized subtypes include MEN 2A, characterized by medullary thyroid carcinoma (MTC), pheochromocytoma (pheo), and hyperparathyroidism (HPT); MEN 2B, by MTC, pheo, and characteristic stigmata; and familial MTC (FMTC), by the presence of MTC only. The purpose of this study was to establish the relationship between specific mutations and the presence of certain disease features in MEN 2 which could help in clinical decision making. DESIGN: Correlative survey study of 477 MEN 2 families. SETTING: Eighteen tertiary referral centers worldwide. PATIENTS: A total of 477 independent MEN 2 families. MAIN OUTCOME MEASURES: Association between the position and type of germline mutation in the RET proto-oncogene and the presence or absence of MTC, pheo, HPT, and/or other features in a family. RESULTS: There is a statistically significant association between the presence of any mutation at a specific position (codon 634) and the presence of pheo and HPT. The presence of a specific mutation, CGC at codon 634, has yet to be associated with FMTC. Conversely, mutations at codons 768 and 804 are thus far seen only with FMTC, while codon 918 mutation is MEN 2B--specific. Rare families with both MEN 2 and Hirschsprung disease were found to have MEN 2-specific codon mutations. Patients with Hirschsprung disease presenting with such mutations should be monitored for the possible development of MEN 2 tumors. CONCLUSIONS: This consortium analysis suggests that genotype-phenotype correlations do exist and, if made reliably absolute, could prove useful in the future in clinical management with respect to screening, surveillance, and prophylaxis, as well as provide insight into the genetic effects of particular mutations.

Carcinoma, Medullary↗
PubMed1996

Transfection with the cDNA of the human thyrotropin receptor of a poorly differentiated rat thyroid cell line (FRT).

A cell line derived from the Fisher rat thyroid (FRT), that does not have functional TSH receptor, was stably transfected with the cDNA of the human TSH receptor (h TSH-R). In wild FRT cells TSH (1-1000 mU/l) was unable to increase cAMP production, while 10-10000 nmol/l forskolin elicited a 10-30 fold cAMP stimulation. Two of the transfected clones were responsive to TSH in terms of cAMP production. In particular, the FRT-R3 transfected clone showed the highest sensitivity to the hormone with a 10 fold cAMP increase over the basal at 100 mU/l TSH. The Northern blot analysis using a 2.4 kbp cDNA probe for the hTSH-R showed a band corresponding to the mRNA of TSH receptor in FRT-R3 cells, but not in wild FRT cells. In both cell types TSH was ineffective in stimulating growth assayed by 3H-thymidine incorporation into DNA. Hybridization with a probe for thyroperoxidase on polymerase chain reaction products after reverse transcription of mRNA showed that FRT-R3, as well as FRT cells, do not have a transcript for thyroperoxidase. In conclusion, the data reported in this paper show that the insertion of the hTSH-R cDNA in the genome of poorly differentiated rat thyroid cells results in the recovery of TSH-dependent adenylate cyclase, but not other differentiated thyroid cell functions.

Adenylyl Cyclases↗
PubMed1996

Somatic mutations of the ret protooncogene in sporadic medullary thyroid carcinoma are not restricted to exon 16 and are associated with tumor recurrence.

Germline point mutations in exons 10, 11, and 16 of the ret protooncogene have been identified as causative in multiple endocrine neoplasia type 2 and in familial medullary thyroid carcinoma (MTC). Somatic point mutations of the same gene, exclusively associated with codon 918 of exon 16, have also been reported in few cases of sporadic medullary thyroid carcinoma. We analyzed the blood and tumor DNA of 19 patients with sporadic MTC and 6 patients with primary parathyroid adenoma for point mutations at exons 10, 11, and 16 of the ret protooncogene by restriction analysis of the PCR-amplified product and by sequence analysis of exons 10 and 11. A Cys634-->Tyr mutation was found in both the tumoral and blood DNA of one patient, indicating that he was affected by an hereditary form of MTC, erroneously considered sporadic. In the other 18 patients with MTC, somatic point mutations of ret were found in 8 cases (44.4%). In 5 cases the mutation affected exon 16 (Met918-->Thr), and in 3 cases it affected exon 11 (Cys634-->Arg in 1 and Cys634-->Trp in 2); these 3 mutations were confirmed by sequence analysis. The remaining 10 patients had no mutation in exon 10 by either restriction analysis or sequence analysis. Clinical data showed that 75% of the patients whose tumor carried ret mutation had tumor recurrence and/or increased serum calcitonin concentrations during the postsurgical follow-up period as opposed to 10% of the patients without mutations (P < 0.02, by chi2 analysis). No ret mutation was found in the tumoral DNA from parathyroid adenomas. Our findings indicate that the somatic ret point mutation frequently found in sporadic MTC may affect not only exon 16 but also exon 11 and is associated with less favorable clinical outcome.

Adult↗
PubMed1995

Early treatment of hereditary medullary thyroid carcinoma after attribution of multiple endocrine neoplasia type 2 gene carrier status by screening for ret gene mutations.

BACKGROUND: Germline missense point mutations of the ret proto-oncogene have been shown as causative in multiple endocrine neoplasia type 2 (MEN 2A and 2B) and in familial medullary thyroid carcinoma (FMTC). Most of the mutations are found in exon 10, 11, or 16 of the gene and are easily recognized by restriction analysis. METHODS: Using restriction analysis, we screened 58 subjects from nine kindreds. RESULTS: Family members (n = 16) already known to be affected with the disease carried the germline mutation. Among the 42 subjects apparently unaffected, 37 were not gene carriers and 5 were gene carriers. Basal and pentagastrin-stimulated serum calcitonin levels were normal in two patients and abnormal in three. All patients were treated with total thyroidectomy and central node dissection. In all cases multiple foci of MTC were shown at histologic examination. CONCLUSIONS: Our data indicate that genetic screening of MEN2 pedigrees allows the early identification of gene carriers. Because surgery of MTC in the preclinical phase has high probability of curing these patients, we suggest genetic screening soon after birth and total thyroidectomy in gene carriers as early as possible.

Base Sequence↗
PubMed1994

Identification of the Cys634-->Tyr mutation of the RET proto-oncogene in a pedigree with multiple endocrine neoplasia type 2A and localized cutaneous lichen amyloidosis.

Following the recent identification of specific germline mutations of the RET proto-oncogene in Multiple Endocrine Neoplasia type 2A (MEN2A) patients, we looked for mutations of this gene in a pedigree showing recurrence of MEN2A and localized Cutaneous Lichen Amyloidosis (CLA). Basal calcitonin and/or pentagastrin test performed in all the 10 available members of this pedigree confirmed the clinical diagnosis and allowed the presymptomatic identification of an additional carrier. A cys634-->tyr missense mutation, already reported as causative in MEN2A patients, was identified after SSCP analysis and direct sequencing of exon 11 of the RET protooncogene in one individual affected with both MEN2A and CLA, thus suggesting a common etiology for the two disorders. Taking advantage of the observation of an RsaI restriction site in the sequence surrounding the mutated codon, we could demonstrate that the same mutation is present in three other affected members, in the presymptomatic carrier and in one additional 25 years old healthy member who shows a mildly positive pentagastrin test.

Amyloidosis↗
PubMed1994

Expression of p21 ras protein as a prognostic factor in papillary thyroid cancer.

We studied the expression of p21, the ras encoded protein, in primary tumour of 45 patients with papillary thyroid cancer (PTC). Patients were grouped according to outcome so that one group (31 patients) had a good outcome and the other (14 patients) a fatal outcome, after a follow-up of at least 5 years. The presence of p21 ras protein was assessed by immunohistochemistry with a specific monoclonal antibody (MAb Y-13259). The results were correlated with the outcome, with the expression of proliferating cell nuclear antigen (PCNA)/cyclin (as a marker of cell proliferation) and with other well established prognostic factors for PTC (age, grading, extension and tumour size; Endocrinol Metab Clin North Am 1990, 19, 545-576). p21 staining in tumours of living patients was negative in 15, weakly positive (1+) in 10 and strongly positive (2+ or more) in 6 patients. In tumours from deceased patients, p21 staining was negative in 1, weakly positive in 2 and strongly positive in the remaining 11 patients (P < 0.001, chi 2). PCNA immunostaining was increased in 63.6% (7/11) of the tumours from deceased patients compared to 17.8% (5/28) of the tumours of living patients, but no direct correlation was found between p21 and PCNA expression. Among the other prognostic factors studied, only age > or = 40 years was a significant predictor of poor outcome. The survival curve of patients with strongly positive p21 staining was similar to that of patients aged > or = 40 years at the time of diagnosis. The combination of p21 > or = 2+ and age > or = 40 was superior to age alone (P < 0.05) as a prognostic indicator of poor outcome. In conclusion, our results indicate that the p21 product of the ras (proto)oncogene is differently expressed in PTC, in relation to the degree of aggressiveness. Regardless of the pathogenetic role of the ras oncogene in thyroid tumorigenesis, our data indicate that the expression of the p21 ras protein may be regarded as a prognostic indicator in PTC. Furthermore, overexpression of p21 ras protein is associated with patients in the older age groups, and might contribute to the poor prognosis of elderly patients.

Adolescent↗
PubMed1994

Disappearance rate of serum calcitonin after total thyroidectomy for medullary thyroid carcinoma.

We studied the half-life of serum calcitonin (CT) in patients subjected to total thyroidectomy for medullary thyroid carcinoma (MTC). One patient showed a rapid serum CT component with a half-life of 3 hours and a slow component with a half-life of 30 hours; in another case only the 30-hour component was found. By chromatography of tumor extracts, we found that all the immunoreactive CT had a molecular weight of 3,600. After surgery, normalization of serum CT was achieved within 15 days in 4 patients, at 3 months and at 6 months in 2 other patients, while 1 patient never normalized. Normalization of serum CT after surgery is not an index of definitive cure in MTC, as demonstrated by one patient who relapsed 3 months after normalization of serum CT. However, as a general rule, patients who reach undetectable serum CT levels soon after surgery, are those having the best prognosis.

Adult↗