Department of Surgical Oncology, Sarcoma Research Center, The University of Texas MD Anderson Cancer Center, Houston, Texas77030-4009, USA.
Histopathology. 2011 Aug;59(2):336-40. doi: 10.1111/j.1365-2559.2011.03932.x.
The utility of CTNNB1 (encoding β-catenin) genotyping for diagnosing sporadic desmoid tumours (DT) when traditional clinicopathological parameters were inconclusive was evaluated.
Cases included were: (i) new primary lesions where initial DT diagnosis was inconclusive; and (ii) possible recurrent DT versus scar. Formalin-fixed paraffin-embedded (FFPE) tissues were obtained via needle biopsy or a surgical excision (57 specimens) as part of initial assessment. DNA extraction, CTNNB1 exon 3 amplification and sequencing were conducted in a Clinical Laboratory Improvement Amendments of 1988 (CLIA)-approved molecular diagnostics laboratory. For patients with no previous DT history (n = 47) sequencing identified mutations in 30 (64%), substantiating DT diagnosis. In biopsies with non-mutated (NM) CTNNB1 (n = 17) the test was inconclusive; in seven of these, a diagnosis of DT was strongly favoured in the subsequent surgical resection specimen. Ten patients with previously resected DT were evaluated; mutation was identified in six cases (60%), indicating DT over scar. In two (20%) with primary tumours harbouring CTNNB1 mutation no mutation was found, favouring scar over DT; the other two NM-CTNNB1 cases (20%) were inconclusive.
CTNNB1 genotyping can be very useful in 'difficult to diagnose' lesions when the differential diagnosis includes DT. Recognizing inherent test limitations, the presence of CTNNB1 mutation can inform the therapeutic approach.
评估 CTNNB1（编码β-连环蛋白）基因分型在传统临床病理参数不确定时对诊断散发性韧带样瘤（DT）的效用。
纳入的病例包括：（i）初始 DT 诊断不确定的新原发性病变；（ii）可能复发的 DT 与疤痕。通过针吸活检或手术切除（57 个标本）获得福尔马林固定石蜡包埋（FFPE）组织，作为初始评估的一部分。在经过临床实验室改进修正案 1988（CLIA）批准的分子诊断实验室中进行 CTNNB1 外显子 3 扩增和测序的 DNA 提取。对于没有先前 DT 病史的患者（n = 47），测序确定了 30 例（64%）存在突变，证实了 DT 的诊断。在 CTNNB1 非突变（NM）的活检中（n = 17），该测试不确定；在其中的 7 例中，在随后的手术切除标本中强烈支持 DT 的诊断。对 10 例先前切除过 DT 的患者进行了评估；在 6 例（60%）中发现了突变，表明 DT 比疤痕更有可能；在 2 例（20%）原发性肿瘤中存在 CTNNB1 突变的情况下未发现突变，更倾向于疤痕而不是 DT；另外 2 例 NM-CTNNB1 病例（20%）不确定。
当鉴别诊断包括 DT 时，CTNNB1 基因分型在“难以诊断”的病变中非常有用。认识到内在的测试局限性，CTNNB1 突变的存在可以为治疗方法提供信息。
