胃印戒细胞癌的研究进展

Advances in the research of gastric signet ring cell carcinoma

近年的流行病学调查发现，胃印戒细胞癌（SRCC）发病率显著升高。本文首先综述了关于SRCC的细胞起源和生物标记物以及SRCC与各种胃癌病理分型之间的关系，并分析胃SRCC的早期诊断率不高可能是由于对病理形成机制和癌前病变并不清楚。胃SRCC的临床特点是肿瘤分化程度低、恶性程度高，在胃癌BorrmannⅣ型（弥漫浸润型）患者中，大多为胃SRCC，故预后不良。胃SRCC平均发病年龄55~61岁，女性胃SRCC的发病率明显多于非SRCC胃癌女性。研究发现，SRCC组织中雌激素和孕激素受体高表达，胃SRCC与性激素具有一定相关性，性激素可能是引起胃SRCC发病性别差异的原因。由于早期胃SRCC淋巴结转移风险较低，对于〈3 cm、没有黏膜下侵袭的中分化肿瘤，或者〈3 cm、高分化、无溃疡和黏膜下病变的胃SRCC患者，可以行内镜黏膜切除术和内镜黏膜下剥离术。对于非转移性晚期胃SRCC，由于淋巴结转移风险太高，所以应手术切除结合足够的淋巴结清扫。辅助化疗也被认为可以改善患者的长期预后，紫杉烷疗法在胃SRCC中可能更有效。近期研究数据表明，胃SRCC和弥漫型胃癌对丝裂霉素C、阿霉素和多西紫杉醇的敏感性显著高于肠型胃癌，但对氟尿嘧啶和顺铂类却不敏感。这些治疗观点有待今后在前瞻性研究中得到证实。

Epidemiological studies in recent years have found that the incidence of gastric signet ring cell carcinoma （SRCC） has increased significantly. In this paper, we first reviewed cell origin and biomarkers of SRCC, and the relationship between SRCC and various pathological types of gastric cancer. The early diagnosis rate of gastric SRCC is low, which may be due to the unclear mechanism of pathology and precancerous lesions. In clinical practice, SRCC has the characteristics of low differentiation and high degree of malignancy. Most of patients with gastric cancer Borrmann IV （diffuse infiltrative type） are gastric SRCC, and their prognosis is poor. The average age of gastric SRCC was 55 to 61 years old. Besides, in female, the incidence of SRCC was significantly higher than that of non-SRCC gastric cancer. It is found that the expressions of estrogen and progesterone receptors in SRCC tissues are high. The relationship between gastric SRCC and sex hormones may be the cause of gender differences in the pathogenesis of gastric SRCC. Due to the low risk of lymph node metastasis in early SRCC, endoscopic mucosal resection and endoscopic submucosal dissection can be performed for 〈3 cm, submucosal invasive, medium differentiated tumors, or 〈3 cm, highly differentiated, ulcerative and submucosal lesions. For non-metastatic advanced gastric SRCC, surgical resection and adequate lymph node dissection should be performed owing to the high risk of lymph node metastasis. Adjuvant chemotherapy is also considered to improve the long-term prognosis of patients. Taxane therapy may be more effective in gastric SRCC. Recent data show that gastric SRCC and diffuse gastric cancer are more sensitive to mitomycin C, doxorubicin and docetaxel than intestinal type gastric cancer, but are not sensitive to fluorouracil and cisplatin. These treatment perspectives still need to be confirmed in future studies.