[A comparative study of breast cancer mass screening and opportunistic screening in Chinese women]

Objective: To compare the population characteristics, the positive rate of screening, the detection rate of breast cancer, early diagnosis rate and the cost between the mass screening group and opportunistic screening group of breast cancer. Methods: This study is a prospective multicenter cohort study conducted from January 1, 2014 to December 31, 2016. The participants were enrolled for mass screening or opportunistic screening of breast cancer. After completing the questionnaire, all the participants received breast physical examination and breast ultrasound examination every year for 3 rounds by year. The participants' characteristics and screening results of the two groups were compared by χ² test, Fisher exact test or Wilcoxon rank-sum test. Results: A total of 20 080 subjects were enrolled. In the mass screening group, 9 434 (100%), 8 111 (85.98%) and 3 940 (41.76%) cases completed the 3 rounds of screening, and 10 646 (100%), 6 209 (58.32%) and 2 988 (28.07%) cases in the opportunistic screening group, respectively. In the opportunistic screening group, the proportions of less than 3 months lactation (1 275/9 796 vs. 1 061/8 860, χ²=4.597, P=0.032), non-fertility (850/10 646 vs. 574/9 434, χ²=27.400, P<0.01), abortion history (6 384/10 646 vs. 5 062/9 434, χ²=81.232, P<0.01), postmenopausal (2 776/10 646 vs. 2 217/9 434, χ²=17.757, P<0.01), long-term oral contraceptives(>6 months) (171/10 646 vs. 77/9 434, χ²=25.593, P<0.01) and family history of breast cancer in first-degree relatives (464/10 646 vs. 236/9 434, χ²=51.257, P<0.01) were significantly higher than those in mass screening group. The positive rate of screening (514/10 646 vs. 128/9 434, χ²=194.736, P<0.01), the detection rate of breast cancer (158/10 646 vs. 13/9 434, χ²=107.374, P<0.01), and positive rate of biopsy (158/452 vs. 13/87, χ²=13.491, P<0.01) in the opportunistic screening group were significantly higher than those of the mass screening group. The early diagnosis rate of the mass screening group was significantly higher than the opportunistic screening group (10/12 vs. 66/141, χ²=5.902, P=0.015). The average cost for detecting each breast cancer case of the mass screening group was 215 038 CNY, which was 13.6 times of the opportunistic screening group (15 799 CNY/case). In the opportunistic screening group, the positive rate of biopsy in primary hospitals was significantly lower than that in large-volume hospitals (79/267 vs. 79/185, χ²=8.267, P=0.004), but there was no significant difference in the mass screening group (6/37 vs. 7/50, χ²=0.082, P=0.774). Conclusions: Breast cancer screening can improve early detection rate. Compared with the mass screening mode, the opportunistic screening mode has the advantages of higher proportion of high-risk factors, higher positive rate of screening, higher detection rate of breast cancer, higher positive rate of biopsy, and lower cost of screening. However, the early diagnosis rate of breast cancer of opportunistic screening is lower than that of mass screening. The positive rate of opportunistic screening in primary hospitals is lower than that of large-volume hospitals. The two screening modes have their own advantages and should be chosen according to local conditions of different regions in China.

REGγ is a strong candidate for the regulation of cell cycle, proliferation and the invasion by poorly differentiated thyroid carcinoma cells

REGγ is a proteasome activator that facilitates the degradation of small peptides. Abnormally high expression of REGγ has been observed in thyroid carcinomas. The purpose of the present study was to explore the role of REGγ in poorly differentiated thyroid carcinoma (PDTC). For this purpose, small interfering RNA (siRNA) was introduced to down-regulate the level of REGγ in the PDTC cell line SW579. Down-regulation of REGγ at the mRNA and protein levels was confirmed by RT-PCR and Western blot analyses. FACS analysis revealed cell cycle arrest at the G₁/S transition, the MTT assay showed inhibition of cell proliferation, and the Transwell assay showed restricted cell invasion. Furthermore, the expression of the p21 protein was increased, the expression of proliferating cell nuclear antigen (PCNA) protein decreased, and the expression of the p27 protein was unchanged as shown by Western blot analyses. REGγ plays a critical role in the cell cycle, proliferation and invasion of SW579 cells. The alteration of p21 and PCNA proteins related to the down-regulation of REGγ suggests that p21 and PCNA participate in the process of REGγ regulation of cell cycle progression and cell proliferation. Thus, targeting REGγ has a therapeutic potential in the management of PDTC patients.

A novel single nucleotide polymorphism of the cyclooxygenase-2 gene associated with breast cancer

AIMS

Cyclooxygenase-2 (COX-2) is involved in carcinogenesis, immune response suppression, apoptosis inhibition, angiogenesis, and tumour cell invasion and metastasis. The gene for COX-2, designated as PTGS2, carries several polymorphisms, such as -765G >C, 1195G/A in the promoter region, and 8473T >C in the 3' UTR, which have been associated with susceptibility to malignant disease. The aim of this study was to search for new mutations and polymorphisms in the COX-2 gene and to assess the relationship with breast cancer.

MATERIALS AND METHODS

In the present study, we identified a novel single nucleotide polymorphism, 169C >G, in exon 2 using polymerase chain reaction-single-strand conformation polymorphism analysis. This nucleotide change causes the amino acid change from proline to alanine at codon 57. To investigate the role of this polymorphism for breast cancer, we determined the prevalence of PTGS2 genotypes in 310 women with breast cancer and 310 gender- and age-matched healthy control subjects.

RESULTS

Homozygous carriers of the 169-GG genotype were more frequent among patients (15.16%) than among controls (9.35%; P = 0.03). The odds ratio for carriers of this genotype for breast cancer was 1.76 (95% confidence interval, 1.20-3.05). Among patients, oestrogen receptor positivity was less frequent among carriers of a GG genotype (61.7%) than among carriers of a CC or GC genotype (72.3%; P = 0.02). Tumour size, histological grade, presence of primary lymph node metastases, progesterone receptor positivity, or age at diagnosis were not associated with PTGS2 genotypes.

CONCLUSION

We conclude that the homozygous PTGS2 169-GG genotype may be associated with breast cancer risk.

Neuroendocrine primary small cell carcinoma of the breast. Report of a case and review of the literature

One case of breast neuroendocrine primary small cell carcinoma with light microscopic and immunohistochemical findings is reported. The patient died of unrelated disease 21 months after diagnosis and treatment by modified radical mastectomy, radiotherapy and subsequent chemotherapy. Immunohistochemical studies revealed cytokeratin and neuroendocrine markers (chromogranin, neuron-specific enolase) immunostaining on tumoral cells. Expression for neuropeptides (met-enkephalin, leu-enkephalin, beta-endorphin) and CALLA antigen was found. Based on this case report and six other previously reported cases, breast neuroendocrine primary small cell carcinoma appears to be a very aggressive tumor for which no firm conclusions regarding treatment can be drawn.