Serik Meirmanov

Cyclin D1 overexpression in thyroid tumours from a radio-contaminated area and its correlation with Pin1 and aberrant β-catenin expression

Cyclin D1 is a target molecule transcriptionally activated by aberrant β‐catenin in Wnt signalling, while prolyl isomerase Pin1 promotes cyclin D1 overexpression directly or through accumulation of β‐catenin in cancer cells. This study aimed to elucidate whether Pin1 was involved in cyclin D1 overexpression and aberrant β‐catenin in thyroid tumourigenesis by examining 14 follicular adenomas (FAa) and 14 papillary thyroid carcinomas (PTCs). All PTCs displayed cyclin D1 overexpression and strong cytoplasmic β‐catenin and/or decreased membrane β‐catenin expression by immunohistochemistry. Overexpression of cyclin D1 mRNA was observed in 45.5% of FAs and 54.5% of PTCs by TaqMan real‐time PCR. Pin1 expression was observed in PTC by immunostaining and was confirmed by reverse transcriptase‐PCR. There was a strong correlation between cyclin D1 and Pin1/cytoplasmic/membrane β‐catenin expression (p < 0.001), and between Pin1 and cytoplasmic (p < 0.001)/membrane (p = 0.002) β‐catenin expression in thyroid tumours. Mutation of the β‐catenin gene could not be detected in PTC. Western blot analysis demonstrated high levels of cyclin D1 and β‐catenin as well as Pin1 expression in a human PTC cell line possessing wild‐type β‐catenin and APC genes. This study suggests that both cyclin D1 overexpression and aberrant β‐catenin expression are of significance in thyroid tumours. Pin1 expression appears to correlate closely with the level of cyclin D1 and aberrant β‐catenin expression in thyroid tumours such as FA and PTC. Pin1 may be an important factor in regulating cyclin D1 and β‐catenin expression during thyroid carcinogenesis. Copyright

Foci formation of P53-binding protein 1 in thyroid tumors: activation of genomic instability during thyroid carcinogenesis.

Defective DNA damage response (DDR) can result in genomic instability (GIN) and lead to the transformation into cancer. P53‐binding protein 1 (53BP1) belongs to a family of evolutionarily conserved DDR proteins. Because 53BP1 molecules localize at the sites of DNA double strand breaks (DSBs) and rapidly form nuclear foci, the presence of 53BP1 foci can be considered as a cytologic marker for endogenous DSBs reflecting GIN. Although it has been proposed that GIN has a crucial role in the progression of thyroid neoplasms, the significance of GIN during thyroid tumorigenesis remains unclear, particularly in patients. We analyzed, therefore, the level of GIN, as detected with immunofluorescence of 53BP1, in 40 cases of resected thyroid tissues. This study demonstrated a number of nuclear 53BP1 foci in thyroid cancers, suggesting a constitutive activation of DDR in thyroid cancer cells. Because follicular adenoma also showed a few 53BP1 nuclear foci, GIN might be induced at a precancerous stage of thyroid tumorigenesis. Furthermore, high‐grade thyroid cancers prominently exhibited an intense and heterogeneous nuclear staining of 53BP1 immunoreactivity, which was also observed in radiation‐associated cancers and in mouse colonic crypts as a delayed response to a high dose ionizing radiation, suggesting increased GIN with progression of cancer. Thus, the present study demonstrated a difference in the staining pattern of 53BP1 during thyroid carcinogenesis. We propose that immunofluorescence analysis of 53BP1 expression can be a useful tool to estimate the level of GIN and, simultaneously, the malignant potency of human thyroid tumors.

Significance of HER2 and C-MYC oncogene amplifications in breast cancer in atomic bomb survivors: associations with radiation exposure and histologic grade.

It has been postulated that radiation induces breast cancers in atomic bomb (A‐bomb) survivors. Oncogene amplification is an important mechanism during breast carcinogenesis and also serves as an indicator of genomic instability (GIN). The objective of this study was to clarify the association of oncogene amplification in breast cancer in A‐bomb survivors with radiation exposure.

Significance of HER2 and C-MYC oncogene amplifications in breast cancer in atomic bomb survivors

It has been postulated that radiation induces breast cancers in atomic bomb (A‐bomb) survivors. Oncogene amplification is an important mechanism during breast carcinogenesis and also serves as an indicator of genomic instability (GIN). The objective of this study was to clarify the association of oncogene amplification in breast cancer in A‐bomb survivors with radiation exposure.

Correlation of cytoplasmic β-catenin and cyclin D1 overexpression during thyroid carcinogenesis around Semipalatinsk nuclear test site

The Semipalatinsk nuclear test site (SNTS), the Republic of Kazakhstan, has been contaminated by radioactive fallout. The alteration of oncogenic molecules in thyroid cancer around the SNTS was considered worthy of analysis because it presented the potential to elucidate the relationship between radiation exposure and thyroid cancer. This study aimed to analyze both beta-catenin and cyclin D1 expressions in thyroid carcinomas around the SNTS. We examined nine cases of chronic thyroiditis, eight cases of follicular adenomas, and 23 cases of papillary carcinomas. Immunohistochemically, all carcinomas displayed a strong cytosolic beta-catenin expression, while both chronic thyroiditis and follicular adenomas showed a significantly lower cytoplasmic beta-catenin (22.2% and 37.5%, respectively). No cyclin D1 immunoreactivity was evident in chronic thyroiditis. In contrast, 62.5% of follicular adenomas and 87.0% of papillary carcinoma showed cyclin D1 overexpression. Additionally, a strong correlation between cytoplasmic beta-catenin and cyclin D1 expression was suggested in thyroid tumors. This study revealed a higher prevalence of both aberrant beta-catenin expression and cyclin D1 overexpression in papillary thyroid cancers around the SNTS than sporadic cases. The analysis of the alteration of the Wnt signaling-related molecules in thyroid cancer around the SNTS may be important to gain an insight into radiation-induced thyroid tumorigenesis.

Small cell carcinoma of the endometrium: Report of a case with analysis of Wnt/β-catenin pathway

Small cell carcinoma of the endometrium (SCCE) is extremely rare. Previous reports indicate that SCCE frequently shows systemic spread and has a poor prognosis. Beta-catenin has been shown to be a key downstream effector of the Wnt signaling pathway, which regulates cell growth and survival. Decreased membranous expression of beta-catenin in cancers correlates with poor prognosis and is associated with dissemination of tumor cells and the formation of metastases. Recently, some different investigators demonstrated aberrant beta-catenin accumulation in neuroendocrine tumors arising in different organs, suggesting a role for the Wnt/beta-catenin signaling pathway during neuroendocrine tumorigenesis. Here, we report a new case of SCCE associated with peritoneal spreading and aggressive course; the patient died one month after surgery. This study also aimed at assessing the involvement of the Wnt signaling pathway in this rare neuroendocrine tumor. Interestingly, both intense nuclear beta-catenin accumulation and cyclin D1 immunoreactivity were restricted to carcinoma cells invading lymphatic vessels. However, mutation analysis failed to demonstrate any mutation in exon 3 of the beta-catenin gene or exon 15 of the APC gene in the present case. Although the mechanism of nuclear accumulation of beta-catenin is still unknown, the heterotopic nuclear localization of beta-catenin may play a role in the tumor invasion process and, subsequently, may be associated with the aggressive behavior of SCCE.

Altered Expression of β-Catenin during Radiation-induced Colonic Carcinogenesis

Summary Radiotherapy for malignant pelvic disease is commonly accompanied by treatment-induced proctitis, and rarely by colorectal cancer. Translocation of the b-catenin protein, which is a key downstream effector of the Wnt signal transduction pathway, is frequently found in colorectal cancer. Nuclear β-catenin enhances transcriptional activity of the cyclin D1 gene in cancer cells. Here, we evaluate the involvement of the Wnt pathway in radiation-induced colon carcinogenesis with rats (n = 36). β-catenin, APC, and cyclin D1 expression profiles were analyzed by immunohistochemistry in radiation-induced chronic colon injury including cancers and ulcerative lesions in rats (n = 12 in treated group, n = 12 in control group). In total, 3 cases of invasive adenocarcinomas were developed in the irradiated portion 50 weeks after a single dose of 36 Gy irradiation.Nuclear translocation of β-catenin was observed in all radiation-induced colon cancers, whereas this protein was also found in the cytoplasm and/or nucleus of 9 cases of non-neoplastic irradiated colonocytes. Nuclear translocation of β-catenin correlated with loss of APC and gain of cyclin D1 expression, suggesting activation of the Wnt pathway during radiation-induced colorectal carcinogenesis. A single dose of 10 Gy was also given for acute injury (n = 12: 3 each in days 0, 3, 5, and 7, respectively). β-catenin expression was distributed in the cytoplasm of degenerating glands at day 3 and 5, and was observed in the cell membrane of those glands with histological normalization at day 7 after irradiation. Because translocation of β-catenin was found in irradiated-colonic mucosa as well as colon cancer, disruption of β-catenin expression might be one of the early events in radiation-induced colonic carcinogenesis.

Sociodemographic factors associated with infant abandonment in maternity hospitals in Kazakhstan: a case–control study

• We studied factors associated with abandonment of infants in maternity wards in Kazakhstan.

Mutational Screening of the BRCA1 Gene in Sporadic Breast Cancer in Kazakhstan Population

To the Editor: In the Republic of Kazakhstan, breast cancer represents one of the most common malignancies and is one of the leading causes of death from cancer in women. To date, little information regarding the role of BRCA1 gene mutations in breast cancer risk among Kazakhstan women has been reported. In this study, we evaluated the frequency and distribution of BRCA1 gene mutations in Kazakhstan women diagnosed with sporadic breast cancer. A total of 83 women with pathologically confirmed breast cancer who had been operated at the large public hospital in Semipalatinsk between 1984 and 2005 were enrolled in this study. Ethics approval was obtained from the special committee of Semipalatinsk State Medical Academy. All women gave written informed consent to be included in the study. Information regarding family history was obtained through interview, and only cases without a family history of affected first-degree or second-degree relatives with breast and ⁄ or ovarian cancer were included. Clinical and pathological characteristics were obtained from patient medical records. A total of 112 healthy women from the Semipalatinsk region without a personal history of malignancy at the time of recruitment were included in the study as controls. The mean age of breast cancer cases and controls was 51.2 ± 9.5 and 52.8 ± 9.1 years, respectively. Genomic DNA was extracted from buccal cell samples of each study participant using the Master Pure DNA purification Kit (EPICENTRE Biotechnologies, Madison, WI) according to the manufacturer’s instructions. Given that exon 11 of BRCA1 gene may vary by 3,426 base pairs, we amplified 10 overlapping regions of this exon using a set of specific primers. All amplified products were then sequenced using the BigDye Terminator v3.1 Cycle sequencing Kit and an ABI 3100 Genetic Analyzer (Applied Biosystems, Foster city, CA). Statistical analysis was undertaken using the SPSS 16.0 (SPSS, Tokyo, Japan). In total, 240 sequence variants in exon 11 of BRCA1 gene were identified in 83 women with sporadic breast cancer, whereas 264 sequence variants were identified in 112 healthy women (Table 1). Deleterious mutations were not detected in either group. With the exception of K1183R, none of the identified sequence variants exhibited any statistically significant differences in allele frequency between the patients and controls. We also found that 42 of the 59 women (71.2%) with breast cancer carried 4–6 co-existing BRCA1 alterations. There were no significant differences between the women diagnosed with breast cancer with and without BRCA1 polymorphisms in terms of mean age at diagnosis, tumor size, and lymph node involvement. We observed a higher prevalence of BRCA1 sequence alterations in 59 of the 83 women (71.1%) with breast cancer and in 65 of the 112 healthy women (58.0%). The missense mutation Q356R was detected more frequently in controls compared with breast cancer patients (Table 1). Dunning et al. (1) have previously reported that the Arg356 allele demonstrated a higher genotype distribution in healthy controls than in breast cancer patients, and may thus play a protective role against breast cancer. In contrast, Janezic et al. (2) reported that the Q356R polymorphism was significantly associated with a family history of ovarian cancer, suggesting that this sequence variant may increase the risk of ovarian cancer development. Tommasi et al. (3) demonstrated that the K1183R polymorphism was inversely related to BRCA1 mutation carrier status and that BRCA1 P871L and E1038G polymorphisms were not significantly related to a higher BRCA1 mutational risk. We found that common polymorphisms in BRCA1 gene appear to be highly prevalent in Kazakhstan breast cancer cases and in healthy controls, which is Address correspondence and reprint requests to: Ainur Akilzhanova, MD, PhD, Division of Tumor and Diagnostic Pathology, Atomic Bomb Disease Institute, Nagasaki University Graduate School of Biomedical Sciences, 1-12-4 Sakamoto, Nagasaki 8528523, Japan, or e-mail: akilzhan_ ainur@mail.ru.

Nuclear Explosions and Public Health Development

More than 60 years ago, on August 6 and 9, two atomic bombs destroyed two Japanese cities: Hiroshima and Nagasaki. It was the first time in history that a single weapon caused such enormous casualties in a population. About 120 000 and 75 000 people of Hiroshima and Nagasaki, respectively, most of whom were civilians, died instantaneously. Doctors and scientists had to contend with a new kind of unknown effect: irradiation. The public health system of Japan, as concerns atomic bomb survivors, has passed several stages of development: from individual dose evaluation to well-organized health care. This unique experience may be applied to other areas, such as cancer screening and elderly care. Over 40 years the USSR has tested nuclear bombs more than 450 times at the Semipalatinsk Nuclear Test Site (SNTS), Kazakhstan. There are many villages and larger settlements, including the city of Semey (distance from SNTS, about 150 km) in the vicinity of the test site. It is believed that hundreds of thousands of inhabitants were more or less exposed to long-term radiation fallout. The government of the Republic of Kazakhstan and the international community, including the government of Japan, have implemented several steps toward research on the influence of radioactive fallout and the support of health care of the Semey region inhabitants. However, research and health care concerning the people of the Semey region still needs improvement. For this purpose, the experience of the Japanese public health system may be useful.