RESUMO
Cowden syndrome is characterized by hamartomatous polyps, trichilemmomas, increased risk of developing neoplasms, and is associated with germline mutations in the PTEN gene. We searched for germline mutations in PTEN in a 49-year-old female patient who presented trichilemmoma with previous history of breast carcinoma, and thyroidectomy for a thyroid nodule. We also searched for somatic mutations in breast and thyroid tumoral tissues. DNA was extracted from peripheral leukocytes, paraffin samples of breast carcinoma, and cytological smears of thyroid nodule fine-needle aspiration biopsy, whose final histopathological diagnosis was adenomatous goiter. PTEN was amplified and sequenced. We identified a novel mutation, due to a T>A inversion at position 159 and A>T inversion at position 160, leading to valine-to-aspartic acid substitution at position 53. The p.Val53Asp was also found in homozygous state in samples obtained from adenocarcinoma breast and thyroid biopsy, denoting loss of heterozygosity. Here, we demonstrated a novel germline mutation in PTEN, as well as somatic loss of the wild-type PTEN allele in breast and thyroid tumors in a patient with Cowden syndrome. Arq Bras Endocrinol Metab. 2012;56(8):592-6.
A síndrome de Cowden é caracterizada por pólipos de hamartoma, triquelomomas, risco aumentado em desenvolver neoplasias e está associada a mutações germinativas no gene PTEN. Procuramos por mutação germinativa no PTEN de uma paciente de 49 anos que apresentou triquilemomas com história pregressa de carcinoma de mama e realizou tireoidectomia devido a nódulo de tireoide. Investigamos também uma mutação somática em tecidos tumorais de mama e tireoide. O DNA foi extraído de leucócitos periféricos, de amostras de parafina de carcinoma de mama e exame citológico de nódulo de tireoide obtido de biópsia por agulha fina, cujo diagnóstico histopatológico foi de bócio adenomatoso. O PTEN foi amplificado e sequenciado. Identificou-se uma nova mutação em decorrência de uma inversão de T>A na posição 159 e A>T na posição 160, levando à substituição de valina para ácido aspártico na posição 53. A mutação p.Val53Asp também foi encontrada em estado homozigoto em amostras obtidas do adenocarcinoma de mama e da biópsia de nódulo tireoidiano, denotando perda de heterozigosidade. Portanto, demonstramos uma mutação germinativa no PTEN e também a perda somática do alelo selvagem PTEN no tumor de mama e da tireoide de uma paciente com síndrome de Cowden. Arq Bras Endocrinol Metab. 2012;56(8):592-6.
Assuntos
Feminino , Humanos , Pessoa de Meia-Idade , Neoplasias da Mama/genética , Síndrome do Hamartoma Múltiplo/genética , Mutação/genética , PTEN Fosfo-Hidrolase/genética , Neoplasias da Glândula Tireoide/genética , Marcadores GenéticosRESUMO
Cowden syndrome is characterized by hamartomatous polyps, trichilemmomas, increased risk of developing neoplasms, and is associated with germline mutations in the PTEN gene. We searched for germline mutations in PTEN in a 49-year-old female patient who presented trichilemmoma with previous history of breast carcinoma, and thyroidectomy for a thyroid nodule. We also searched for somatic mutations in breast and thyroid tumoral tissues. DNA was extracted from peripheral leukocytes, paraffin samples of breast carcinoma, and cytological smears of thyroid nodule fine-needle aspiration biopsy, whose final histopathological diagnosis was adenomatous goiter. PTEN was amplified and sequenced. We identified a novel mutation, due to a T>A inversion at position 159 and A>T inversion at position 160, leading to valine-to-aspartic acid substitution at position 53. The p.Val53Asp was also found in homozygous state in samples obtained from adenocarcinoma breast and thyroid biopsy, denoting loss of heterozygosity. Here, we demonstrated a novel germline mutation in PTEN, as well as somatic loss of the wild-type PTEN allele in breast and thyroid tumors in a patient with Cowden syndrome.