英国科研人员最近首次证实,妊娠期间患癌的孕妇会将癌症遗传给胎儿。
萨里郡萨顿癌症研究所近日以日本一个罕见案例作为研究对象。
在这一案例中,一名28岁孕妇产后被确诊为血癌,并在数周后不治身亡,而她的女儿在11个月大时也被确诊患上同样癌症。血液检查发现,女婴的癌细胞生来就有,来自于母体。
传统生物医学理论认为,即使癌细胞能够穿越胎盘这道天然屏障,也会被胎儿的免疫系统阻拦,因而孕妇不会把癌症传给胎儿。
但癌症研究所研究人员进一步调查发现,这名女婴的癌细胞中缺少一种重要的脱氧核糖核酸(DNA),令她的免疫系统无法将癌细胞认定为“入侵者”而加以消灭,从而使癌细胞在其体内存活发展。
这一研究结果刊登在最新一期的《国家科学院学报》上。
尽管此前曾有过30多个母婴患同种癌症的案例,但人们从未能证实婴儿的疾病源于母体。英国《每日邮报》12日引述领导此项研究的梅尔·格里夫斯教授的话报道:“在这个案例中,母体的癌细胞的确能穿过胎盘、进入正在发育的胚胎并成功植入,因为胎儿的免疫系统无法发现它们(癌细胞)。”
研究人员说,恶性黑素瘤也能通过这种方式由母体传给婴儿。但与此同时,其他癌症以同样方式传递的可能性不大。格里夫斯也说,日本的这一案例极为罕见,胎儿面临从母体遗传癌症的危险性非常低。
英国癌症研究会教授彼得·约翰逊说:“这是一个极其不寻常的案例,但是这项研究具有启发性,它表明癌细胞只有绕过婴儿的免疫系统才能入侵他们体内,产生病变。”
“它的重要性在于进一步证明癌细胞在生长之前必须要绕过免疫系统,我们有希望通过提高病人免疫系统对癌细胞的‘预警标准’来研制出新的癌症诊疗方法,”约翰逊乐观表示。
英国白血病研究慈善基金会科技主管戴维·格兰特补充说:“这项引人瞩目的研究告诉我们,白血病细胞可以被免疫系统消灭,……我们今后将重点研究如何利用免疫系统力量,治疗并保护人们远离白血病。”(生物谷Bioon.com)
生物谷推荐原始出处:
PNAS October 12, 2009, doi: 10.1073/pnas.0904658106
Immunologically silent cancer clone transmission from mother to offspring
Takeshi Isodaa,1, Anthony M. Fordb,1, Daisuke Tomizawaa, Frederik W. van Delftb, David Gonzalez De Castrob, Norkio Mitsuikia, Joannah Scorec, Tomohiko Takid, Tomohiro Morioa, Masatoshi Takagia, Hiroh Sajie, Mel Greavesb,2,3 and Shuki Mizutania,2,3
aDepartment of Pediatrics and Developmental Biology, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 1138519, Japan;
bSection of Haemato-Oncology, Institute of Cancer Research, Brookes Lawley Building, 15 Cotswold Road, Sutton, Surrey SM2 5NG, United Kingdom;
cWessex Regional Genetics Laboratory, University of Southampton, Salisbury District Hospital, Salisbury SP2 8BJ, United Kingdom;
dDepartment of Molecular Laboratory Medicine, Kyoto Prefectural University of Medicine Graduate School of Medical Science, 465 Kajii Cho, Hirokoji-agaru, Kawaramachi, Kamigyo-ku, Kyoto 6028566, Japan; and
eHuman Leukocyte Antigen Laboratory, Ebis Building, 3-4F, 82 Shimo-Tsutsumimachi, Marutamachi-kudaru, Kawabata Dori, Sakyo-ku, Kyoto 606-8396, Japan
Rare cases of possible materno-fetal transmission of cancer have been recorded over the past 100 years but evidence for a shared cancer clone has been very limited. We provide genetic evidence for mother to offspring transmission, in utero, of a leukemic cell clone. Maternal and infant cancer clones shared the same unique BCR-ABL1 genomic fusion sequence, indicating a shared, single-cell origin. Microsatellite markers in the infant cancer were all of maternal origin. Additionally, the infant, maternally-derived cancer cells had a major deletion on one copy of chromosome 6p that included deletion of HLA alleles that were not inherited by the infant (i.e., foreign to the infant), suggesting a possible mechanism for immune evasion.