美国男性乳腺癌患者的确诊年龄往往比女性大 5 - 10 岁 。 4.2 遗传因素 种系致病性变异（Pathogenic Variants，PVs）在 BRCA2 基因是男性乳腺癌的重要风险因素，而 BRCA1 PVs 与男性乳腺癌的关联尚不明确。携带 BRCA2 PVs 的男性患乳腺癌的风险比非携带者高得多，70 岁时 ...

Meiosis is the specialized form of cell division by which most sexually reproducing organisms generate haploid gametes. In a diploid organism, each meiotic cell begins prophase I with four copies of ...