Yuki Naruke

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.

Thyroid papillary carcinoma with solid sclerosing change in IgG4-related sclerosing disease

IgG4‐related sclerosing disease (IgG4‐RSD) is an inflammatory and fibrosing disorder characterized by lymphoplasmacytic inflammation with infiltration of various organs, including the pancreas, bile ducts, lung, kidney, and retroperitoneum. As for malignancy in IgG4‐RSD, only limited literature is available. We report here a case of thyroid papillary carcinoma showing unique morphology in IgG4‐RSD. Solid tumor nests were surrounded by dense IgG4‐positive plasma cells and fibrosis at both the primary site and metastatic lymph nodes. In contrast the background thyroid showed focal lymphocytic thyroiditis. IgG4‐related sclerosing sialadenitis and autoimmune pancreatitis were also diagnosed, and prednisolone treatment improved symptoms and serum IgG4 abnormality. To the best of our knowledge, this is the first documentation of a malignancy of the thyroid gland occurring in a background of IgG4‐RSD. A brief review of the literature on the relationship between IgG4 and malignancy is included.

Immunohistochemical analyses of beta-catenin and cyclin D1 expression in giant cell tumor of bone (GCTB): a possible role of Wnt pathway in GCTB tumorigenesis.

Giant cell tumor of bone (GCTB) is a benign neoplasm but occasionally shows local recurrence, and histologically consists of osteoclast-like giant cells (GC) and stromal mononuclear cells (SC), which are capable of proliferation and osteoblastic differentiation. Activation of Wnt signaling can induce osteoblast differentiation and osteoclastgenesis during bone resorption process. This study analyzed the profiles of beta-catenin and cyclin D1 expression in GCTB to elucidate an involvement of Wnt pathway in tumorigenesis. We performed immunohistochemistry for beta-catenin, cyclin D1, and Ki-67 in 16 GCTB tumors, including 5 recurrent cases that were surgically resected. All 16 cases of GCTB displayed beta-catenin, cyclin D1, and Ki-67 expression. Immunoreactivity for beta-catenin was observed in nuclei of SC and GC. Cyclin D1 immunoreactivity was found mainly in nuclei of GC, while Ki-67 immunoreactivity was restricted to nuclei of SC. The nuclear beta-catenin labeling index (LI) in both SC (60.6 vs. 41.8%, p=0.074) and GC (41.7 vs. 20.1%, p=0.095) was higher in recurrent tumors than in primary tumors in all the 4 cases. However, Ki-67 LI in SC (18.8 vs. 19.9%, p=0.851) and cyclin D1 LI in GC (55.4 vs. 70.1%, p=0.225) were not higher in recurrent tumors than in primary tumors. Our results suggested activation of Wnt/ beta-catenin pathway in GCTB tumorigenesis. Since cyclin D1 in GC was never associated with the expression of the well-known proliferative marker Ki-67, cyclin D1 expression might play a role in GC formation instead of promoting cell proliferation during GCTB tumorigenesis. Importantly, it was suggested that the nuclear beta-catenin staining level might be associated with tumor recurrence in GCTB.

Aberrant expression of interferon regulatory factor 3 in human lung cancer

We analyzed the subcellular distributions and gene structures of interferon regulatory factor 3 (IRF3) transcription factor in 50 cases of human primary lung cancer. The immunohistochemical analyses revealed substantially aberrant IRF3 expression specific to the cancer lesions (2 and 6 tumors with nuclear staining, and 4 and 5 tumors with negative staining, in adenocarcinoma and squamous cell carcinoma, respectively), while the morphologically normal region around the tumors exhibited only cytoplasmic staining. In addition, we determined the sequence of the entire IRF3 coding region, and found two novel variants with the amino acid changes (S(175)(AGC)-->R(175)(CGC) and A(208)(GCC)-->D(208)(GAC)). The R(175) variant was also detected in a morphologically normal region around the nuclear staining squamous cell carcinoma, and exhibited almost the same functions as the wild type IRF3. On the other hand, the D(208) variant, found in the negative staining squamous cell carcinoma cases, reduced the nuclear translocation in response to IkappaB kinase epsilon stimulation, as compared to the wild type IRF3, but the same variant was detected in the surrounding morphologically normal region. The aberrant expression of IRF3 and the novel D(208) variant may provide clues to elucidate the etiology of primary lung cancer.

Genomic instability in the epidermis induced by atomic bomb (A-bomb) radiation: a long-lasting health effect in A-bomb survivors.

Radiation etiology is suggested in the occurrence of basal cell carcinoma (BCC) of the skin among atomic bomb (A‐bomb) survivors. Any genotoxicity, including ionizing radiation, can induce a DNA damage response (DDR), leading to genomic instability (GIN), which allows the accumulation of mutations during tumorigenesis. In this study, the authors evaluated the presence of GIN in the epidermis of survivors as a late effect of A‐bomb radiation.

Alteration of p53-binding protein 1 expression during skin carcinogenesis: association with genomic instability.

Epidermal cells are the first cells to be exposed to environmental genotoxic agents such as ultraviolet and ionizing radiations, which induce DNA double strand breaks (DSB) and activate DNA damage response (DDR) to maintain genomic integrity. Defective DDR can result in genomic instability (GIN) which is considered to be a central aspect of any carcinogenic process. P53‐binding protein 1 (53BP1) belongs to a family of evolutionarily conserved DDR proteins. Because 53BP1 molecules localize at the sites of DSB and rapidly form nuclear foci, the presence of 53BP1 nuclear foci can be considered as a cytological marker for endogenous DSB reflecting GIN. The levels of GIN were analyzed by immunofluorescence studies of 53BP1 in 56 skin tumors that included 20 seborrheic keratosis, eight actinic keratosis, nine Bowens disease, nine squamous cell carcinoma, and 10 basal cell carcinoma. This study demonstrated a number of nuclear 53BP1 foci in human skin tumorigenesis, suggesting a constitutive activation of DDR in skin cancer cells. Because actinic keratosis showed a high DDR type of 53BP1 immunoreactivity, GIN seems to be induced at the precancerous stage. Furthermore, invasive cancers exhibited a high level of intense, abnormal 53BP1 nuclear staining with nuclear accumulation of p53, suggesting a disruption of DDR leading to a high level of GIN in cancer cells. The results of this study suggest that GIN has a crucial role in the progression of skin carcinogenesis. The detection of 53BP1 expression by immunofluorescence can be a useful histological marker to estimate the malignant potential of human skin tumors. (Cancer Sci 2008; 99: 946–951)

Significance of p53-binding protein 1 (53BP1) expression in thyroid papillary microcarcinoma: association with BRAFV600E mutation status.

In a previous report, we proposed that analysis of 53BP1 expression by immunofluorescence could be a useful tool in estimating the level of genomic instability (GIN), as well as the malignant potential, of thyroid tumours. In an attempt to clarify the value of 53BP1 expression as a new molecular marker for the aggressiveness of thyroid papillary microcarcinoma (PMC), we assessed the association between the type of 53BP1 expression and clinicopathological features such as tumour size, extrathyroidal invasion, lymph node metastasis and BRAFV600E mutation of PMC.

De novo papillary renal cell carcinoma in an allograft kidney: Evidence of donor origin

To the Editor: An increased incidence of primary malignancies has been recognized in transplant recipients. Renal cell carcinomas (RCC) represent 4.6% of all malignancies in renal transplant recipients, whereas RCC constitutes 2% of all cancers in the general population. According to the Cincinnati Transplant Tumor Registry, there are fewer instances of RCC that develop in the allograft kidneys (up to 10%), while nearly 90% of RCC in renal transplant recipients have been found in native kidneys. De novo RCC has been described as the opposite of pre-existing tumors before transplantation. Pathological characteristics of de novo RCC occurring in the allograft kidney have not been well described. Furthermore, genetic studies to determine the tumor origin, whether from the donor or the recipient, have been performed in only a few reported RCC cases, although it is clinically important considering the association of tumor transmission. We report a case of de novo papillary RCC developing in an allograft kidney diagnosed 13 years after renal transplantation, and which was genetically confirmed to be of donor origin. A 49-year-old Japanese male presented with end-stage renal disease secondary to chronic glomerulonephritis of unknown etiology when he was at the age of 25. The patient had no family history of renal disease. After 5 years of hemodialysis, he underwent renal transplantation at the age of 29 from a deceased donor. The donor was a 37-year-old Japanese male who died of cerebral hemorrhage. The donor had no significant medical illness in his family history or past history according to medical records. Immunosuppressive therapy was maintained with methylprednisolone, cyclosporine and mizoribine. The patient presented with an episode of chronic rejection that successfully treated by steroids 7 years after transplantation. At that point, ultrasonography showed no evidence of a solid or cystic lesion in the allograft kidney. Graft function had been stable with serum creatine level of 1.1 to 1.3 mg/dL, although the patient exhibited 30 mg/dL of proteinuria on rare occasions. However, 13 years after transplantation, ultrasonography revealed a 2.3 cm solitary cystic lesion in the lower pole of the allograft kidney. During the following 7 years, the cyst had increased in size to 4.0 cm with slight blood flow inside, which led to suspicion of malignancy. There was no other cystic lesion in the allograft kidney or native kidneys. An extensive workup ruled out any primary or metastatic lesion. The patient underwent a partial nephrectomy of the allograft kidney in 2010, 20 years after transplantation. No recurrence has been found on most recent evaluation. Graft function has resumed and the patient has maintained dialysis-free status. The contralateral kidney of this particular donor, which had been transplanted to a Japanese female and resected 12 years after transplantation due to chronic rejection, presented no solid or cystic lesion. In the resected specimen, a well-circumscribed tumor was located in the renal cortex. The tumor measured 4.0 ¥ 3.5 ¥ 3.5 cm in size. The cut surface was solid and yellowish-white with tiny hemorrhages. No necrosis was noted. Histologically, a unilocular cyst was densely filled with small cuboidal cells with scanty basophilic cytoplasm. The cuboidal cells also lined the cyst wall (Fig. 1a). The tumor cells formed papillae and tubules, arranged in a single layer on the basement membrane. The nuclei were small, uniform and had hyperchromatic chromatin with a finely granular pattern. The papillary cores frequently contained aggregates of foamy macrophages and hemosiderin laden macrophages. Kidney parenchyma around the tumor showed mild interstitial fibrosis and slight tubular atrophy. Formalin-fixed paraffinembedded tissue sections were immunohistochemically stained. The antibodies used were vimentin (DAKO, Glostrup, Denmark, monoclonal, clone V9, dilution 1:100), high molecular weight cytokeratin (DAKO, monoclonal, clone 34bE12, dilution 1:100), cytokeratin 7 (DAKO, monoclonal, clone OV-TL12/30, dilution 1:100), CD10 (DAKO, monoclonal, clone SS2/36, dilution 1:100), and alpha-methylacylcoenzyme A racemase (AMACR) (DAKO, monoclonal, clone 13H4, dilution 1:100). Prostate tissue and the allograft kidney parenchyma around the tumor were used as positive control. The tumor cells were positive for vimentin, cytokeratin 7 (Fig. 1b), CD10 and AMACR, but negative for high molecular weight cytokeratin (Fig. 1c). Pathological diagnosis was papillary RCC type 1, Fuhrman’s nuclear grade 2, and stage pT1aN0M0. Comparative microsatellite analysis was performed to detect tumor origin according to a previously described method. Recipient peripheral blood and paraffinembedded tissue from the tumor and the allograft kidney parenchyma (donor tissue) were used. In total, 15 short tandem repeat (STR) markers were compared for microsatellite analysis. All of the analyzed STR markers were detected and the predominant DNA patterns of the tumor matched those of the donor, confirming that the tumor was of donor origin (Fig. 1d). The present case provides some insights into the nature of de novo RCC developing in an allograft kidney. First, the present case of RCC was confirmed to be of donor origin by microsatellite analysis on genomic DNA. It is of clinical Pathology International 2011; 61: 694–696 doi:10.1111/j.1440-1827.2011.02714.x