Using short tandem repeat analysis for choriocarcinoma diagnosis: a case series

Abstract

Background Choriocarcinoma is a highly aggressive, malignant trophoblastic neoplasm that can be gestational or non-gestational in origin. Accurate discrimination between these two subtypes, the causative pregnancy type, and the pregnancy-to-treatment interval for gestational choriocarcinoma are vital for clinical management. Methods Fifteen choriocarcinomas were genotyped using multiplex fluorescent polymerase chain reaction amplification of 15 short tandem repeat (STR) loci and the amelogenin locus (XY determination). Genotype patterns at each locus from tumoral and maternal tissues were compared, and any prior or concurrent mole/placenta was also compared when available. According to STR results showing the presence or absence of the paternal chromosomal complement, the gestational or non-gestational origin of the tumor and the nature of the causative pregnancy was identified. Results Fourteen tumors were gestational. Of these, seven were androgenetic/homozygous XX, and two were androgenetic/heterozygous XX, indicating that the causative pregnancies were molar pregnancies. Among the nine molar pregnancies, five were of the occult type. A menopausal patient developed a tumor from a mole that occurred seven years ago, identified by the genetically identical allele from the tumor and prior mole. One tumor originating from a previous mole was interrupted by term delivery. Two tumors found eight weeks postpartum were identified as originating from a prior occult mole. A pelvic choriocarcinoma was separated from a genetically distinct third trimester intrauterine placenta. Five gestational tumors were biparental: 2 XX, 3 XY. Of three ovarian tumors, two were confirmed gestational (1 androgenetic/homozygous XX; 1 biparental XY), and one was an ovarian tumor (XX) with a complete match of the genotype for all 15 loci, therefore ascertaining its non-gestational origin. Conclusion Gestational choriocarcinoma can originate in an androgenetic or biparental manner. The majority are androgenetic/homozygous XX, while a large number of them might be occult molar pregnancies. The origin of ectopic androgenetic choriocarcinoma with concurrent intrauterine placenta might be from either dispermic twin gestation (mole and coexistent nonmolar fetus) or an antecedent molar pregnancy. Choriocarcinoma shortly postpartum might not be associated with the last placenta. STR analysis can be useful in distinguishing gestational choriocarcinoma from non-gestational, as well as the causative pregnancy, and serve as a helpful examination tool for guiding clinical management.

Clinical features of a Chinese female nongestational choriocarcinoma cohort: a retrospective study of 37 patients

“…Genotyping can identify the presence of a parental allele, confirming a diagnosis of GC, since NGC has only maternal alleles. Based on this distinguishing feature, genetic analysis is applied by increasing studies and is not considered controversial [21,22]. However, since genetic analysis is not widely used for choriocarcinoma patients, clinical diagnosis should still be the primary method.…”

Clinical features of a Chinese female nongestational choriocarcinoma cohort: a retrospective study of 37 patients

“…Second, there is a small possibility that some ovarian NGCs may originate from ectopic ovarian pregnancies. Even though ovarian pregnancy is one of the rarest forms of ectopic pregnancy, having an incidence of 1/7000-1/40,000 in live births and only 0.5-3% of all ectopic gestations, patients with previous ectopic ovarian pregnancy were also excluded [20]. Some studies insist that NGC patients should have no pregnancy history [1].…”

Clinical features of a Chinese female Non-gestational Choriocarcinoma cohort: a retrospective study of 37 patients

“…Based on this distinguishing feature, genetic analysis was applied by more and more studies and considered with low controversy [19,20]. However, since genetic analysis is not widely put into use for choriocarcinoma patients, clinical diagnosis should still be the mainstream.…”